Crosslinked tinted polymers

ABSTRACT

The invention relates to a novel process for the production of tinted mouldings, in particular tinted contact lenses, in which a crosslinkable tinted polymer comprising units containing a crosslinkable group and units containing a reactive dye radical is crosslinked in solution, and to tinted mouldings, in particular tinted contact lenses, obtainable by this process. The present invention likewise relates to novel crosslinkable tinted polymers comprising units containing a crosslinkable group and units containing a reactive dye radical which can be employed in the novel process, in particular derivatives of a polyvinyl alcohol having a molecular weight of at least about 2000, to crosslinked tinted polymers, either homopolymers or copolymers, made from these novel crosslinkable tinted polymers containing a reactive dye radical, a process for the preparation of the novel crosslinkable tinted polymers comprising units containing a crosslinkable group and units containing a reactive dye radical and the homopolymers and copolymers obtainable therefrom, to tinted mouldings made from said homopolymers or copolymers, in particular tinted contact lenses made from these homopolymers or copolymers, and to a process for the production of tinted contact lenses using said homopolymers or copolymers.

The invention relates to a novel process for the production ofmouldings, in particular contact lenses, in which a crosslinkable tintedpolymer is crosslinked in solution, and to mouldings, in particularcontact lenses, which are obtainable by this process.

The present invention also relates to novel crosslinkable tintedpolymers comprising units containing a crosslinkable group and unitscontaining a covalently bonded reactive dye radical which can beemployed in the novel process, in particular those based on startingpolymers containing functional groups, for example hydroxyl groups, onthe polymer chain or functional groups, for example imino groups, in thepolymer chain or functional groups bonded to the polymer skeleton via abridge, where these functional groups allow covalent bonds to compoundscontaining a crosslinkable modifier group or another modifier group.These starting polymers are, in particular, polyhydroxyl compoundshaving a 1,2-and/or 1,3-diol structure, such as polyvinyl alcohol, orhydrolysed copolymers of vinyl acetate, for example copolymers withvinyl chloride, N-vinylpyrrolidone, etc. The invention furthermorerelates to crosslinked novel polymers, either homopolymers orcopolymers, made from these novel crosslinkable tinted polymers, to aprocess for the preparation of the novel crosslinkable tinted polymersand the homopolymers and copolymers obtainable therefrom, to mouldingsmade from said homopolymers or copolymers, in particular contact lensesmade from these homopolymers or copolymers, and to a process for theproduction of contact lenses using the said homopolymers or copolymers.

Tinted or coloured contact lenses are known. Conventional contact lensesare only tinted or coloured after their final shaping by subsequentapplication of a reactive dye tinting taking place on the surface (forexample in accordance with EP-A-0 388 357 and EP-A-0 072 353). Thistinting process is followed by at least a neutralization step, anextraction step and a rinsing step, ie the completion of the lensestakes a considerable time.

One of the objects of the present invention was substantially to reduceor completely to eliminate these time-consuming production steps.

This object is achieved in accordance with the invention on the one handby the provision of novel crosslinkable tinted polymers comprising unitscontaining a crosslinkable group and units containing a covalentlybonded reactive dye radical, and on the other hand by crosslinking thesecrosslinkable tinted polymers directly, preferably in water, inparticular by photocrosslinking, very rapidly to give crosslinked tintedpolymers, in particular tinted contact lenses.

The invention thus consists in, in particular, carrying out the tintingof contact lenses before their final shaping. This overcomes alldisadvantages known from the prior art mentioned, and in particular thetime-consuming neutralization steps and extraction steps for completionof the lenses are eliminated.

The present invention relates, in particular, to starting polymers(homopolymers and copolymers) which contain a functional group on thepolymer chain, for example a hydroxyl (aliphatic or phenolic), amino,amido, thio or carboxyl group, or functional derivatives thereof, orwhich contain a functional group in the polymer chain, for example animino group, which can then react directly with a reactive dye moleculeor can react with a group which contains a crosslinkable group or agroup containing a reactive dye. Besides the reactive dye molecule andthe crosslinkable group, the polymer backbone can, if desired, alsocontain further modifiers.

The starting polymers are preferably derivatives of polyvinyl alcohol orcopolymers of vinyl alcohol which contain a 1,3-diol skeleton. Thecrosslinkable group and the group containing a reactive dye radical canbe bonded to the polymer skeleton in various ways, for example, in thecase of a group containing a crosslinkable group, through a certainpercentage of the 1,3-diol units being modified to give a 1,3-dioxanewhich contains a crosslinkable radical in the 2-position. Thecrosslinkable radical is, in particular, an aminoalkyl radical with acrosslinkable group bonded to its nitrogen atom. This is preferably aderivative of a polyvinyl alcohol having a mean molecular weight of atleast about 2000 which comprises from about 0.5 to about 80%, based onthe number of hydroxyl groups in the polyvinyl alcohol, of units of theformula I ##STR1## in which R is alkylene having up to 12 carbon atoms,R₁ is hydrogen or lower alkyl, and R₂ is an olefinically unsaturated,electron-withdrawing, copolymerizable radical, preferably having up to25 carbon atoms, and R₃ is hydrogen, a C₁ C₆ alkyl group or a cycloalkylgroup. R₂ is, for example, an olefinically unsaturated acyl radical ofthe formula R₃₀ --CO--, in which R₃₀ is an olefinically unsaturated,copolymerizable radical having 2 to 24 carbon atoms, preferably having 2to 8 carbon atoms, particularly preferably having 2 to 4 carbon atoms.In another embodiment, the radical R₂ is a radical of the formula II

    --CO--NH--(R.sub.4 --NH--CO--O).sub.q --R.sub.5 --O--CO--R.sub.30(II)

in which q is zero or one, and R₄ and R₅, independently of one another,are lower alkylene having 2 to 8 carbon atoms, arylene having 6 to 12carbon atoms, a saturated bivalent cycloaliphatic group having 6 to 10carbon atoms, arylenealkylene or alkylenearylene having 7 to 14 carbonatoms or arylenealkylenearylene having 13 to 16 carbon atoms, and inwhich R₃₀ is as defined above.

The crosslinkable polymer is therefore in particular a derivative of apolyvinyl alcohol having a molecular weight of at least about 2000 whichcomprises units of the formula III ##STR2## in which R is loweralkylene, R₁ is hydrogen or lower alkyl, p has the value zero or one, qhas the value zero or one, R₃₀ is an olefinically unsaturated,copolymerizable radical having 2 to 8 carbon atoms, and R₄ and R₅,independently of one another, are lower alkylene having 2 to 8 carbonatoms, arylene having 6 to 12 carbon atoms, a saturated bivalentcycloaliphatic group having 6 to 10 carbon atoms, arylenealkylene oralkylenearylene having 7 to 14 carbon atoms or arylenealkylenearylenehaving 13 to 16 carbon atoms.

Alkylene R preferably has up to 12 carbon atoms and can be linear orbranched. Suitable examples include octylene, hexylene, pentylene,butylene, propylene, ethylene, methylene, 2-propylene, 2-butylene and3-pentylene. Lower alkylene R preferably has up to 6, particularlypreferably up to 4 carbon atoms. Methylene and butylene are particularlypreferred.

R₁ is preferably hydrogen or lower alkyl having up to seven, inparticular up to four, carbon atoms, in particular hydrogen.

Lower alkylene R₄ or R₅ preferably has 2 to 6 carbon atoms and is, inparticular, linear. Suitable examples include propylene, butylene,hexylene, dimethylethylene and, particularly preferably, ethylene.

Arylene R₄ or R₅ is preferably phenylene, which is unsubstituted orsubstituted by lower alkyl or lower alkoxy, in particular 1,3-phenyleneor 1,4-phenylene or methyl- 1,4-phenylene.

A saturated bivalent cycloaliphatic group R₄ or R₅ is preferablycyclohexylene or cyclohexylene(lower alkylene), for examplecyclohexylenemethylene, which is unsubstituted or substituted by one ormore methyl groups, for example trimethylcyclohexylenemethylene, forexample the bivalent isophorone radical.

The arylene unit of alkylenearylene or arylenealkylene R₄ or R₅ ispreferably phenylene, unsubstituted or substituted by lower alkyl orlower alkoxy, and the alkylene unit thereof is preferably loweralkylene, such as methylene or ethylene, in particular methylene.Radicals R₄ or R₅ of this type are therefore preferablyphenylenemethylene or methylenephenylene.

Arylenealkylenearylene R₄ or R₅ is preferably phenylene(loweralkylene)phenylene having up to 4 carbon atoms in the alkylene unit, forexample phenyleneethylenephenylene.

The radicals R₄ and R₅ are preferably, independently of one another,lower alkylene having 2 to 6 carbon atoms, phenylene, unsubstituted orsubstituted by lower alkyl, cyclohexylene or cyclohexylene(loweralkylene), unsubstituted or substituted by lower alkyl, phenylene(loweralkylene), (lower alkylene)phenylene or phenylene(loweralkylene)phenylene.

For the purposes of this invention, the term "lower" in connection withradicals and compounds denotes, unless defined otherwise, radicals orcompounds having up to 7 carbon atoms, preferably having up to 4 carbonatoms.

Lower alkyl has, in particular, up to 7 carbon atoms, preferably up to 4carbon atoms, and is, for example, methyl, ethyl, propyl, butyl ortert-butyl.

Lower alkoxy has, in particular, up to 7 carbon atoms, preferably up to4 carbon atoms, and is, for example, methoxy, ethoxy, propoxy, butoxy ortert-butoxy.

The olefinically unsaturated, copolymerizable radical R₃₀ having 2 to 24carbon atoms is preferably alkenyl having 2 to 24 carbon atoms, inparticular alkenyl having 2 to 8 carbon atoms, particularly preferablyalkenyl having 2 to 4 carbon atoms, for example ethenyl, 2-propenyl,3-propenyl, 2-butenyl, hexenyl, octenyl or dodecenyl. Ethenyl and2-propenyl are preferred, so that the --CO--R₃₀ group is the acylradical of acrylic acid or methacrylic acid.

The bivalent group --R₄ --NH--CO--O-- is present if q is one and absentif q is zero. Crosslinkable polymers in which q is zero are preferred.

The bivalent group --CO--NH--(R₄ --NH--CO--O)_(q) --R₅ --O-- is presentif p is one and absent if p is zero. Crosslinkable polymers in which pis zero are preferred.

In the crosslinkable polymers in which p is one, the index q ispreferably zero. Particular preference is given to crosslinkablepolymers in which p is one, the index q is zero and R₅ is loweralkylene.

A preferred novel polymer is therefore in particular a derivative of apolyvinyl alcohol having a molecular weight of at least about 2000 whichcomprises units; of the formula III in which R is lower alkylene havingup to 6 carbon atoms, p is zero and R₃₀ is alkenyl having 2 to 8 carbonatoms.

A further preferred crosslinkable polymer is therefore in particular aderivative of a polyvinyl alcohol having a molecular weight of at leastabout 2000 which comprises units of the formula III in which R is loweralkylene having up to 6 carbon atoms, p is one, q is zero, R₅ is loweralkylene having 2 to 6 carbon atoms, and R₃₀ is alkenyl having 2 to 8carbon atoms.

A further preferred crosslinkable polymer is therefore in particular aderivative of a polyvinyl alcohol having a molecular weight of at leastabout 2000 which comprises units of the formula III in which R is loweralkylene having up to 6 carbon atoms, p is one, q is one, R₄ is loweralkylene having 2 to 6 carbon atoms, phenylene, unsubstituted orsubstituted by lower alkyl, cyclohexylene or cyclohexylene(loweralkylene), unsubstituted or substituted by lower alkyl, phenylene(loweralkylene), (lower alkylene)phenylene or phenylene(loweralkylene)phenylene, R₅ is lower alkylene having 2 to 6 carbon atoms, andR₃₀ is alkenyl having 2 to 8 carbon atoms.

One way of fixing the reactive dye other than directly to the polymerbackbone comprises reacting the reactive dye with, for example, an aminogroup of a compound which then serves as a bridge to the polymer chain.Suitable such bridges are all bivalent and trivalent groups which on theone hand form a covalent bond to the polymer backbone and on the otherhand contain the covalently bonded reactive dye radical. From the largenumber of such bridges, mention may be made by way of example of acetaland ketal bridges.

The units containing a reactive dye radical covalently bonded to thepolymer backbone conform, in particular, to the formulae IV, IVA, IVBand IVC below ##STR3## in which:

RF' is the radical of the formula ##STR4## D is a radical of an organicdye, R₁₄ is a divalent electron-withdrawing group,

U is hydrogen or halogen,

R is a divalent radical of a C₁ -C₁₂ alkane,

R₁ is hydrogen or C₁ -C₄ alkyl,

R₃ is hydrogen, C₁ -C₆ alkyl or cycloalkyl, and

Y is --O-- or --N(R₁)--.

Polyvinyl alcohols which can be derivatized preferably have a meanmolecular weight of at least 2000, in particular about 10,000. The upperlimit to their molecular weight is up to 1,000,000. The polyvinylalcohols preferably have a molecular weight of up to 300,000, inparticular of up to 100,000, very particularly preferably of up to about50,000.

Suitable polyvinyl alcohols usually have principally a 1,3-diolstructure. However, the derivatized crosslinkable polyvinyl alcohols canalso contain hydroxyl groups in the form of 1,2-glycols, such ascopolymer units of 1,2-dihydroxyethylene, as can be obtained, forexample, by alkaline hydrolysis of vinyl acetate-vinylene carbonatecopolymers.

In addition, the derivatized polyvinyl alcohols can also contain smallproportions, for example of up to 20%, preferably of up to 5%, ofcopolymer units of ethylene, propylene, acrylamide, methacrylamide,dimethacrylamide, hydroxyethyl methacrylate, methyl methacrylate, methylacrylate, ethyl acrylate, vinylpyrrolidone, hydroxyethyl acrylate, allylalcohol, styrene or similar comonomers usually used.

Polyvinyl alcohols (PVA) which can be used as starting polymers arecommercially available polyvinyl alcohols, for example Vinol® 107 fromAir Products (MW=22,000 to 31,000, 98-98.8% hydrolysed), Polysciences4397 (MW=25,000, 98.5% hydrolysed), BF 14 from Chan Chun, Elvanol® 90-50from DuPont and UF-120 from Unitika. Other producers are, for example,Nippon Gohsei (Gohsenol®), Monsanto (Gelvatol®), Wacker (Polyviol®) orthe Japanese producers Kuraray, Denki and Shin-Etsu. However, it isadvantageous to use Mowiol® products from Hoechst, in particular thoseof the 3-83, 4-88, 4-98, 6-88, 6-98, 8-88, 8-98, 10-98, 20-98, 26-88 and40-88 type.

The PVAs are prepared by basic or acidic, partial or virtually completehydrolysis of polyvinyl acetate.

As mentioned above, it is also possible to use copolymers of hydrolysedor partially hydrolysed vinyl acetate, which are obtainable, forexample, as hydrolysed ethylene-vinyl acetate (EVA), or vinylchloride-vinyl acetate, N-vinylpyrrolidone-vinyl acetate and maleicanhydride-vinyl acetate.

Polyvinyl alcohol is usually prepared by hydrolysis of the correspondinghomopolymeric polyvinyl acetate. In a preferred embodiment, thepolyvinyl alcohol derivatized in accordance with the invention comprisesless than 50% of polyvinyl acetate units, in particular less than 20% ofpolyvinyl acetate units. Preferred amounts of residual acetate units inthe polyvinyl alcohol derivatized in accordance with the invention are,based on the total amount of vinyl alcohol units and acetate units, fromabout 2 to 20%, preferably from about 2 to 16%, in particular from 2 to12%, especially from 0.5 to 3%.

Polyvinyl alcohols comprising units of the formula III can be preparedin a manner known per se. For example, a polyvinyl alcohol having a meanmolecular weight of at least about 2000 which comprises units of theformula VI

    --CH(OH)--CH.sub.2 --                                      (VI)

can be reacted with from about 0.5 to 80%, based on the number ofhydroxyl groups in the compound of the formula VI, of a compound of theformula (VII) ##STR5## in which R' and R", independently of one another,are hydrogen, lower alkyl or lower alkanoyl, such as acetyl orpropionyl, and the other variables are as defined under the formula III,in particular in an acidic medium.

Alternatively, a polyvinyl alcohol having a molecular weight of at leastabout 2000 and which comprises units of the formula VI can be reactedwith a compound of the formula VIII ##STR6## in which the variables areas defined for the compound of the formula VII, in particular underacidic conditions, and the resultant cyclic acetal can subsequently bereacted with a compound of the formula IX

    OCN--(R.sub.4 -NH-CO-O).sub.q --R.sub.5 --O--CO--R.sub.30  (IX)

in which the variables are as defined for the compound of the formulaVII.

Alternatively, the product obtainable as described above from a compoundof the formula VI and a compound of the formula VIII can be reacted witha compound of the formula (X)

    X--CO--R.sub.30                                            (X)

in which R₃₀ is, for example, alkenyl having 2 to 8 carbon atoms, and Xis a reactive group, for example etherified or esterified hydroxyl, forexample halogen, in particular chlorine.

Compounds of the formula VII in which p is zero are disclosed, forexample, in EP 201 693. Compounds of the formula VIII are also describedtherein. Compounds of the formula IX are known per se or can be preparedin a manner known per se. An example of a compound of the formula IX inwhich q is zero is isocyanatoethyl methacrylate. An example of acompound of the formula IX in which q is one is a product of thereaction of isophorone diisocyanate with 0.5 equivalent of hydroxyethylmethacrylate. Compounds of the formula X are known per se, a typicalrepresentative being methacryloyl chloride. Compounds of the formula VIIin which p and/or q is 1 can be prepared in a manner known per se fromthe abovementioned compounds, for example by reacting a compound of theformula VIII with isocyanatoethyl methacrylate or by reacting a compoundof the formula VIII with isophorone diisocyanate which has previouslybeen terminated with 0.5 equivalent of hydroxyethyl methacrylate.

Polyvinyl alcohols comprising units of the formula IVB can be preparedin a manner known per se. For example, a polyvinyl alcohol having a meanmolecular weight of at least about 2000 which comprises units of theformula VI

    --CH(OH)--CH.sub.2 --                                      VI

can be reacted with a compound of the formula XI ##STR7## in which thesymbols R' and R" are hydrogen, lower alkyl or lower alkanoyl, and theother symbols R₃, R, R₁, and RF' are as defined above, inaqueous/alkaline medium, for example in a sodium carbonate solution, atfrom room temperature to about 40° C.

The compounds of the formula XI are novel and represent a furthersubject-matter of the invention.

These compounds of the formula XI are obtained, for example, by reactingan ωaminoaldehyde acetal, such as ω-aminoacetaldehyde dimethyl acetal or4-aminobutyraldehyde diethyl acetal, with a compound which introducesthe reactive dye radical RF', for example one of the formula

    D--R.sub.14 --CH(U)--CH.sub.2 --O--SO.sub.3 Na

in which D, U and R₁₄ are as defined under the formulae IV to IVC.Reactive dyes which can be used are in particular those which are knownas "reactive dyes which form ether bonds". These dyes contain reactivegroups which react with cellulose to form an ether bond. They aredescribed in general terms in Fiber-Reactive Dyes, Chapter VI, by W. F.Beech, SAF International, Inc., New York (1970). U.S. Pat. No. 4,553,775(Su) likewise mentions typical examples of commercially available dyeswhich can be used.

Of the reactive dye types which are suitable for the novel use, mentionmay be made, for example, of the following general classes: reactivedyes containing vinyl sulfone precursors, such asβ-sulfatoethylsulfonyl, β-sulfatoethylsulfonamido,β-hydroxyethylsulfonyl and β-hydroxyethylsulfonamido substituents, andsuitable derivatives thereof; dyes containing acryloylamino,β-chloropropionylamino and β-sulfatopropionylamino groups and relatedreactive groups; dyes containing β-phenylsulfonylpropionylamino groups;dyes containing β-sulfato or β-chloroethylsulfamoyl groups; chloroacetyldyes; α-bromoacryloyl dyes; and many other reactive dyes developed foruse in the dyeing of natural and synthetic fibres, in particularcellulose or wool, which act by nucleophilic addition reactions.

Some typical examples of commercially available dyes which are suitablefor the novel use are dye--SO₂ --CH₂ CH₂ --O--SO₃ Na (Remazol), dye--SO₂NHCH₂ CH₂ OSO₃ Na (Levafix), dye--NH-OC-CH₂ CH₂ SO₂ C₆ H₅ (Solidazol),##STR8##

The invention also covers the use of dyes containing more than onereactive group (albeit in very small amounts) which is suitable for theformation of a covalent bond by nucleophilic addition reaction withhydroxyl, amino or mercapto groups.

Reactive dyes which are particularly suitable for formation of acovalent bond with the hydroxyl, amino, amido or mercapto groups presentin the simple or derivatized crosslinkable polymer are those of thegeneral formulae XVII or XVIII ##STR9## in which D is the radical of anorganic dye; R₁₄ is a divalent, organic, electron-withdrawing groupwhich is suitable for withdrawing electrons from the carbon atoms in the##STR10## groups in the formulae XVII and XVIII and thus activatingthem;

U is hydrogen or halogen, and

V is a leaving group, or mixtures thereof.

The organic dye radical D is preferably the radical of an azo (monoazoor disazo), phthalocyanine, azomethine, nitro, metal complex oranthraquinone dye.

The reactive dyes of the formula XVIII eliminate HV in the reactionmedia, forming intermediates of the formula XVII, which subsequentlyreact by nucleophilic addition.

The divalent group --R₁₄ -- can be bonded directly to an aromatic ringcarbon of D or can be bonded thereto via an aliphatic group, such as analkylene group, for example a lower alkylene group.

Suitable divalent groups R₁₄ include, for example, --CO--, --SO₂ --,--SO--, --NHCO--, --NHSO₂ --, --SO₂ NH-- and the like. R₁₄ is mostpreferably --SO₂ --, --SO₂ NH--, --CO-- or --NHCO--, especially --SO₂--.

If U is halogen, it is most preferably chlorine or bromine.

Suitable leaving groups V include --Cl, --Br, --OH, di(loweralkyl)amino, ##STR11##

--SO₂ --phenyl, --OSO₃ ⁻ --Z⁺, in which Z⁺ is a cation, --OSO₃ R₁₅ or--OSO₂ R₁₅, in which R₁₅ is in each case alkyl, aryl, aralkyl oralkaryl.

If R₁₅ is alkyl, it is advantageously alkyl having 1 to 6 carbon atoms,and preferably alkyl having 1 to 4 carbon atoms. If R₁₅ is aryl, it ispreferably phenyl or naphthyl. If R₁₅ is alkaryl, it is preferably(lower alkyl)-substituted phenyl, such as tolyl or xylyl, and if R₁₅ isaralkyl, it is preferably phenyl(lower alkyl), such as benzyl orphenethyl.

The present invention also covers the use of halotriazine dyes, inparticular chlorotriazine dyes, obtainable from Ciba-Geigy AG. Thesetypically have the formula ##STR12## in which D' is a radical of anorganic dye of the abovementioned type, which is bonded to the triazinering either directly or via a suitable linker, T is a solubilizingmoiety, halogen or a further D', and Z₁ is halogen, preferably fluorine,chlorine or bromine, in particular fluorine or chlorine, most preferablychlorine. If two halogen groups are present, these can be identical toor different from one another. If two groups D' are present, these canbe identical to or different from one another. Corresponding dyes orradicals are known to the person skilled in the art, for example fromEP-A-388 356.

Mention may be made by way of example of an anthraquinone dye(dichlorotriazinyl derivative), such as Reactive Blue 4, and an azo dye(dichlorotriazinyl derivative), such as Reactive Red 11.

Particularly preferred reactive dyes which can be used for tintingcrosslinkable polymers have the trade names Remazol Schwarz B (ReactiveBlack 5), Remazol Brillantblau R (Reactive Blue 19, Duasyn-Blau R-R),Remazol Turkisblau G (Reactive Blue 21, Duasyn-Blau R-KG), RemazolGoldorange 3G (Reactive Orange 78), Remazol Brillantrot F3B (ReactiveRed 180, Duasyn-Rot R-F3B), Remazol Gelb GR (Reactive Yellow 15),Remazol Brillantgelb GL (Reactive Yellow 37, Duasyn-Gelb R-GL),Duasyn-Gelb R-R (mixture of Reactive Yellow 17 and Reactive Yellow 15),Remazol Brillantgriin 6B (Reactive Blue 38, Duasyn-Grun R-K6B), RemazolSchwarz RL (Reactive Black 31, Duasyn-Schwarz R-KRL), Duasyn-Schwarz R-N(mixture of Reactive Black 5 and Reactive Orange 72), RemazolBrillantorange 3R (Reactive Orange 16), Remazol

Brillantblau B, Remazol Brillantblau BB, Remazol Druckschwarz G, RemazolRot B, and Duasyn-Blau R-UG.

For further illustration, the following shows the bonding of a reactivedye to a polymer backbone, either directly or via a bridge, where, inthese formulae, D is a reactive dye radical, for example the radical ofRemazol Brillantblau R of the following formula: ##STR13##

The following formulae, which serve for further illustration, conform tothe formulae IVC, IVA, IVB and IV (in this sequence): ##STR14##

The concentration of the reactive dyes in the crosslinkable polymer canbe up to 5% and is in particular in the range from 0.001 to 3%, inparticular from 0.01 to 2%.

The tinting process is generally followed by a neutralization process,for example with 0.01N HCl solution, after which the crosslinkabletinted polymer is purified.

The following are further starting polymers comprising, for example,copolymer units in the polymer chain which are derived from thefollowing monomer units : a vinyllactam (a), vinyl alcohol (b), ifdesired a vinyl (lower alkane)carboxylate (c), a vinylic crosslinkingagent (d) and, if desired, a vinylic photoinitiator (e).

Preferred starting polymers comprise units derived from the followingmonomer units in the copolymer chain:

5-85 percent by weight of a vinyllactam (a),

3-80 percent by weight of vinyl alcohol (b),

0-65 percent by weight of a vinyl (lower alkane)carboxylate (c),

3-40 percent by weight of a vinylic crosslinking agent (d) and

0-5 percent by weight of a vinylic photoinitiator (e).

Preference is furthermore given to a starting polymer comprising unitsderived from the following monomer units in the copolymer chain:

10-75 percent by weight of a vinyllactam (a),

10-65 percent by weight of vinyl alcohol (b),

2-40 percent by weight of a vinyl (lower alkane)carboxylate (c),

5-35 percent by weight of a vinylic crosslinking agent (d) and

0-3 percent by weight of a vinylic photoinitiator (e).

Of particular interest are starting polymers comprising units derivedfrom the following monomer units in the copolymer chain:

20-70 percent by weight of a vinyllactam (a),

15-60 percent by weight of vinyl alcohol (b),

5-30 percent by weight of a vinyl (lower alkane)carboxylate (c),

7-30 percent by weight of a vinylic crosslinking agent (d) and

0-2 percent by weight of a vinylic photoinitiator (e).

The term vinyllactam (a) here is taken to mean, for example, a five- toseven-membered lactam of the formula (XII) ##STR15## where R₆ is linearor branched (if desired multiply branched) alkylene or alkenylene having2 to 8 carbon atoms, and A is CO or CR₇ R₈, where R₇ is hydrogen, loweralkyl, aryl, aralkyl or alkaryl, and R₈ is hydrogen or lower alkyl.

Some N-vinyllactams (a) conforming to the above structural formula (XII)are N-vinyl-2-pyrrolidone, N-vinyl-2-piperidone, N-vinyl-2-caprolactam,N-vinyl-:3-methyl-2-pyrrolidone, N-vinyl-3-methyl-2-piperidone,N-vinyl-3-methyl-2-caprolactam, N-vinyl-4-methyl-2-pyrrolidone,N-vinyl-4-methyl-2-caprolactam, N-vinyl-5-methyl-2-pyrrolidone,N-vinyl-5-methyl-2-piperidone, N-vinyl-5,5-dimethyl-2-pyrrolidone,N-vinyl-3,3,5-trimethyl-2-pyrrolidone,N-vinyl-5-methyl-5-ethyl-2-pyrrolidone,N-vinyl-3,4,5-trimethyl-3-ethyl-2-pyrrolidone,N-vinyl-6-methyl-2-piperidone, N-vinyl-6-ethyl-2-piperidone, N-vinyl-3,5-dimethyl-2-piperidone, N-vi nyl-4,4-dimethyl-2-piperidone,N-vinyl-7-methyl-2-caprolactam, N-vinyl-7-ethyl-2-caprolactam,N-vinyl-3,5-dimethyl-2-caprolactam, N-vinyl4,6-dimethyl-2-caprolactam,N-vinyl-3,5,7-trimethyl-2-caprolactam, N-vinylmaleimide andN-vinylsuccinimide. If desired, mixtures thereof, can also be used.

A preferred vinyllactam (a) is a heterocyclic monomer of the formula XIIcontaining 4 to 6 carbon atoms in the heterocyclic ring, in particular 4carbon atoms in the heterocyclic ring, more preferably a heterocyclicmonomer of the formula XII containing 4 carbon atoms in the heterocyclicring in which R₇ is hydrogen or lower alkyl.

Another more preferred vinyllactam (a) is a heterocyclic monomer of theformula XII containing 4 carbon atoms in the heterocyclic ring in whichR₇ and R₈, independently of one another, are hydrogen or lower alkyl. Ahighly preferred vinyllactam (a) is N-vinyl-2-pyrrolidone.

The term vinyl(lower alkane)carboxylate (c) is taken to mean, forexample, vinyl heptanoate, vinyl hexanoate, vinyl pentanoate, vinylbutanoate, vinyl propanoate (vinyl propionate) or vinyl ethanoate (vinylacetate). Mixtures of said vinyl esters (c) can likewise be used.Preferred vinyl(lower alkane)carboxylates (c) are vinyl acetate, vinylpropionate and mixtures of the two.

The term vinylic crosslinking agent (d) is taken to mean, for example, aderivative of the formula (XIII)

    R.sub.9 --(CO).sub.n --(X.sup.1 --B--X.sup.1 --CO).sub.m --(X.sup.1 --B--X2--CO).sub.r --O--CH═CH.sub.2 (XIII)

in which R₉ is a hydrocarbon group which can be polymerized by means offree radicals; n, m and r, independently of one another, are zero orone; the radicals B, independently of one another, are divalent radicalshaving up to 20 carbon atoms; radicals X¹, independently of one another,are --O--, --NH-- or a single bond; and X² is NH or a single bond.

R₉ is, for example, alkenyl as a group, preferably having 2 to 12 carbonatoms, which can be polymerized by means of free radicals. Examples ofalkenyl are vinyl, allyl, 1-propen-2-yl, 1-buten-2- or -3- or -4-yl,2-buten-3-yl, the isomers of pentenyl, hexenyl, octenyl, decenyl anddodecenyl. R₉ preferably contains 2 to 12, particularly preferably 2 to8, especially preferably 2 to 4, carbon atoms.

The divalent radical B is, for example, lower alkylene, arylene, asaturated bivalent cycloaliphatic group having 6 to 12 carbon atoms,alkylenearylene, arylenealkylene or arylenealkylenearylene.

A preferred vinylic crosslinking agent (d) is, for example, a compoundof the formula (XIII) in which the polymerizable group R₉ is alkenylhaving 2 to 8 carbon atoms; n, m and r, independently of one another,are zero or 1; the radicals B, independently of one another, are loweralkylene, arylene, a saturated bivalent cycloaliphatic group having 6 to12 carbon atoms, alkylenearylene, arylenealkylene orarylenealkylenearylene; the radicals X¹, independently of one another,are --O--, --NH-- or a single bond; and X² is NH or a single bond.

A preferred vinylic crosslinking agent (d) is, for example, a compoundof the formula (XII) in which the polymerizable group R₉ is alkenylhaving 2 to 8 carbon atoms; n, m and r, independently of one another,are zero or 1; the radicals B, independently of one another, are loweralkylene, arylene, a saturated bivalent cycloaliphatic group having 6 to12 carbon atoms, alkylenearylene or arylenealkylene; the radicals X¹independently of one another, are --O--, --NH-- or a single bond; and X²is NH or a single bond. The radicals B are preferably, independently ofone another, lower alkylene, arylene or a saturated bivalentcycloaliphatic group having 6 to 12 carbon atoms.

Another preferred vinylic crosslinking agent (d) is a compound of theformula (XIII) in which the polymerizable group R₉ is alkenyl having 2to 8 carbon atoms; n=1 or 0, and n and r are zero.

A particularly preferred vinylic crosslinking agent (d) is, for example,a compound of the formula (XIII) in which the polymerizable group R₉ isalkenyl having 2 to 4 carbon atoms; m and n are one and r=1 or 0; theradicals B, independently of one another, are lower alkylene, arylene ora saturated bivalent cycloaliphatic group having 6 to 12 carbon atoms;the radicals X¹ independently of one another, are --O--, --NH-- or asingle bond; and X² is NH or a single bond.

A very preferred vinylic crosslinking agent (d) is, for example, acompound of the formula (XIII) in which the polymerizable group R₉ isalkenyl having 2 to 4 carbon atoms; m and n are one and p=1 or 0; theradicals B, independently of one another, are lower alkylene; theradicals X¹, independently of one another, are --O--, --NH-- or a singlebond; and X² is NH or a single bond.

Vinylpyrrolidone-vinyl alcohol copolymers can also be derivatized andthus crosslinked via an acetal structure.

The term vinylic photoinitiator (e) is taken to mean, for example, aderivative of the formula (XIV)

    CH.sub.2 ═CH--OCOX.sup.2 --B--X.sup.2 COY--PI          (XIV)

where the radicals X², independently of one another, are NH or a singlebond; Y is --O--, --S-- or --NH--; B is a divalent radical having up to20 carbon atoms; and PI is a radical of a photoinitiator minus YH.

A preferred vinylic photoinitiator (e) is, for example, a compound ofthe formula (XIV) in which the radicals X², independently of oneanother, are NH or a single bond; Y is --O-- or --NH--; B is a divalentradical and is, for example, lower alkylene, arylene, a saturatedbivalent cycloaliphatic group having 6 to 12 carbon atoms,alkylenearylene, arylenealkylene or arylenealkylenearylene; and PI isthe radical of a photoinitiator of the formula (XV) shown below minusYH. In this formula, Y is preferably --O--. Furthermore, independentlyof this preference for Y, B is preferably lower alkylene, arylene or asaturated bivalent cycloaliphatic group having 6 to 12 carbon atoms.

The term photoinitiator PI-YH is taken to mean, for example, a compoundof the formula (XV) ##STR16## in which Y is --O--, --S-- or --NH--; X¹is --O--, --NH-- or a single bond; Z is lower alkylene, arylene, asaturated bivalent cycloaliphatic group having 6 to 12 carbon atoms,alkylenearylene, arylenealkylene or arylenealkylenearylene; and R₁₀ is aradical of the formula (XVI) ##STR17## in which R₁₁ is lower alkyl orlower alkoxy; R₁₂ is selected from lower alkyl, lower alkoxy andaralkyl; and R₁₃ is hydroxyl, di(lower alkyl)amino, aryl orazacyclooxaalkyl.

Preferred examples of radicals R₁₀ of the formula (XVI) are ##STR18##

Highly preferred is furthermore a vinylic photoinitiator (e) in whichthe radicals X₂, independently of one another, are NH or a single bond;Y is --O--; B is a divalent radical, for example lower alkylene, aryleneor a saturated bivalent cycloaliphatic group having 6 to 12 carbonatoms; and PI is the radical of, for example, 2-hydroxy-1 -4-(2-hydroxyethoxy)phenyl!2-methylpropan-1-one minus the primaryhydroxyl group.

For the purposes of this invention, the term "lower" in connection withradicals and compounds denotes, unless defined otherwise, in particularradicals or compounds having up to 7 carbon atoms, preferably having upto 4 carbon atoms.

Lower alkyl can be linear or branched and has, in particular, up to 7carbon atoms, preferably up to 4 carbon atoms, and is, for example,methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl or tert-butyl.

Analogously, the term (lower alkane)carboxylic acid is taken to mean alinear or branched aliphatic carboxylic acid having up to 7 carbonatoms, preferably having up to 4 carbon atoms. Examples are acetic acid,propionic acid and butyric acid.

Alkylene has up to 10 carbon atoms and can be linear or branched.Suitable examples include decylene, octylene, hexylene, pentylene,butylene, propylene, ethylene, methylene, 2-propylene, 2-butylene and3-pentylene. Alkylene is preferably lower alkylene.

Lower alkylene denotes alkylene having up to 7 carbon atoms,particularly preferably having up to 4 carbon atoms. Particularlypreferred meanings of lower alkylene are methylene and ethylene.

Alkenylene has up to 10 carbon atoms and can be linear or branched.Suitable examples include decenylene, octenylene, hexenylene, butenyleneand ethenylene. Alkenylene is preferably lower alkenylene.

Lower alkenylene denotes alkenylene having up to 7 carbon atoms,particularly preferably having up to 4 carbon atoms. A particularlypreferred meaning of lower alkenylene is ethenylene.

Aryl is, for example, naphthyl, pyridyl, thienyl or preferably phenyl,unsubsituted or substituted by lower alkyl or lower alkoxy.

Lower alkoxy has, in particular, up to 7 carbon atoms, preferably up to4 carbon atoms, and is, for example, methoxy, ethoxy, propoxy ortert-butoxy.

Aralkyl is preferably phenyl(lower alkyl) having up to 4 carbon atoms inthe alkyl unit, for example 1- or 2-phenylethyl or benzyl.

Alkaryl is preferably (lower alkyl)phenyl having up to 4 carbon atoms inan alkyl unit, for example ethylphenyl, tolyl or xylyl.

Arylene is preferably phenylene, unsubstituted or substituted by loweralkyl or lower alkoxy, in particular 1,3-phenylene, 1,4-phenylene ormethyl-1,4-phenylene.

A saturated bivalent cycloaliphatic group is preferably cyclohexylene orcyclohexylene(lower alkylene), for example cyclohexylenemethylene,unsubstituted or substituted by one or more lower alkyl groups, forexample methyl groups, such as trimethylcyclohexylenemethylene, forexample the bivalent isophorone radical.

Cycloalkyl has, in particular, up to 7 carbon atoms, preferably 3 to 6carbon atoms, and is, for example, cyclopropyl, cyclobutyl, cyclopentylor cyclohexyl.

The term azacyclooxaalkyl is taken to mean an oxygen-containingsaturated azacycloalkyl radical in which the oxygen is incorporated intothe ring and azacycloalkvl is a nitrogen-containing cycloalkyl radical.A typical example of an azacyclooxaalkane is morpholine.

These polymers are advantageously prepared, for example, already from asuitable starting polymer, for example from the product of thepolymerization of an N-vinyllactam (a) and a vinyl (loweralkane)carboxylate (c). Examples of such starting polymers areN-vinylpyrrolidone-vinyl acetate, N-vinylpyrrolidone-vinyl propionate ormixed esters, namely N-vinylpyrrolidone-vinyl acetate/vinyl propionate.

The last-mentioned starting polymers are commercially available invarious mean molecular weights and in various compositions.

Aldrich markets, for example, N-vinylpyrrolidone-vinyl acetate (VP-VAc)polymer as 60/40 copolymer (60% by weight of VP, 40% by weight of VAc)which is a powder and has a molecular weight of M_(n) =56 000. Aldrichalso markets VP-VAc 30/70 in isopropanol.

A further supplier of VP-VAc starting polymers is BASF, which marketsthese polymers under the name Luviskol VA. Examples are Luviskol VA 28,Luviskol VA 37 and Luviskol VA 73 having a molecular weight of M_(n)=7000-22 000 (PMMA). Luviskol VA 37 HM is a high-molecular-weightstarting polymer having an M_(n) of 32 000 (PMMA).

The numerical coding of these Luviskols indicates the composition. Forexample, Luviskol VA 28 means that this is a VP-VAc starting polymercomprising about 20% by weight of VP and about 80% by weight of VAc.

The molecular weights (M_(n)) are determined by gel permeationchromatography (GPC) {size exclusion chromatography (SEC)} using DMF assolvent, and relate, unless otherwise stated, to polymethyl methacrylate(PMMA) calibration standard.

The N-vinyllactam (a)-vinyl (lower alkane)carboxylate (c) startingpolymers can be partially or fully hydrolysed under acid or alkalineconditions. Partial hydrolysis gives terpolymers comprising the unitsvinyllactam (a), vinyl alcohol (b) and vinyl (lower alkane)carboxylate(c), for example a terpolymer of vinylpyrrolidone, vinyl acetate andvinyl alcohol. Complete hydrolysis gives a starting polymer comprisingthe units vinyllactam (a) and vinyl alcohol (b). Starting polymershydrolysed in this way can be derivatized in a suitable manner, forexample using methacryloyl chloride, a 1:1 addition product of toluenediisocyanate (TDI) and hydroxyethyl methacrylate (HEMA), a 1:1 additionproduct of isophorone diisocyanate (IPDI) and HEMA, or isocyanatoethylmethacrylate (IEM). Derivatization allows the type and amount, forexample of the crosslinking agent component (d), to be determined andincorporated into the crosslinkable polymer.

An N-vinyllactam (a)-vinyl alcohol (b) starting polymer can bederivatized analogously, for example again using a suitable precursor ofa vinylic photoinitiator (e). A precursor of this type is derived, forexample, from the above formula (XIV), it being possible to formulate aprecursor of this type by, for example, formal subtraction of vinylalcohol in the formula (XIV). Derivatization of the starting polymer togive a crosslinkable polymer comprising a photoinitiator component (e)can take place simultaneously with or after the incorporation of acrosslinking agent component (d).

The molecular weight of a polymer is determined primarily through asuitable choice of the starting polymer, for example a commercialN-vinylpyrrolidone-vinyl acetate polymer. The derivatization describedabove only changes the molecular weight comparatively marginally and canin addition be controlled precisely through the choice, for example, ofthe crosslinking agent component and the degree of hydrolysis of thestarting polymer. The molecular weights (M_(n)) of such polymersgenerally vary in the range of M_(n) =2000-200 000 g/mol. The molecularweight is preferably in the range from 5000 to 200 000 g/mol, and verypreferably in the range from 10 000 to 100 000 g/mol.

The crosslinkable polymers can be prepared in the presence or absence ofa solvent. Suitable solvents are in principle all solvents whichdissolve both a starting polymer and a crosslinkable polymer to beprepared and in addition are substantially inert. Examples thereof arewater, alcohols, such as lower alkanols, for example ethanol ormethanol, furthermore carboxamides, such as dimethylformamide (DMF) ordimethylacetamide (DMA), ethers, for example diethyl ether,tetrahydrofuran (THF) or diethylene glycol dimethyl ether (diglyme),furthermore dimethyl sulfoxide, and mixtures of suitable solvents, forexample mixtures of an alcohol with an ether, for example ethanol/THF,or methanol/diethyl ether. Preference is given to lower alkanols,carboxamides and dimethyl sulfoxide.

The preparation of crosslinkable polymers, in particular during andafter incorporation of the crosslinking agent component (d) andespecially of the photoinitiator component (e), should be carried out inthe absence of light in order to prevent uncontrolled and prematurecrosslinking. It is also advantageous if atmospheric oxygen is notexcluded during the synthesis of the crosslinkable polymers or is evenadmixed, since oxygen acts as a free-radical scavenger during thesynthesis. Any free radicals present are scavenged, suppressinguncontrolled crosslinking. The oxygen thus acts as a stabilizer.

The composition of a crosslinkable polymer is the principal determinant,after it has been crosslinked, of the properties of a resultantmoulding, for example a hydrogel contact lens. The crosslinking agentcomponent (d) in a crosslinkable polymer can principally serve tocontrol the mechanical properties of a contact lens. The water contentof, for example, a hydrogel contact lens is determined, for example, bythe vinyllactam (a) or vinyl alcohol (b) content in the crosslinkablepolymer.

In addition to the abovementioned units, the novel water-soluble,crosslinkable polymers can also comprise further modifier units. Of themany possibilities for such modifiers, the following are mentioned byway of example:

Further units containing crosslinkable groups are, for example, those ofthe formulae A and B ##STR19## in which R₁ and R₂ embody amino acidradicals and are, independently of one another: hydrogen, a C₁ -C₈ alkylgroup, an aryl group or a cyclohexyl group, these groups beingunsubstituted or monosubstituted or polysubstituted,

R₃ is hydrogen or a C₁ -C₄ alkyl group, and

R₄ is an --O-- or --NH-- bridge.

Further units containing crosslinkable groups are, for example, those ofthe formula C ##STR20## in which R is a linear or branched bivalentradical of a C₁ -C₁₂ alkane, preferably of a C₁ -C₆ alkane,

R₁ is hydrogen, a C₁ -C₆ alkyl group or a cycloalkyl group, preferably acyclohexyl group,

R₂ is hydrogen or a C₁ -C₆ alkyl radical,

R₃ is the ##STR21## group if n=0, or the ##STR22## bridge if n =1, R₄ ishydrogen or C₁ -C₄ alkyl,

n is zero or 1, preferably 0, and

R₁₆ and R₁₇, independently of one another, are hydrogen, linear orbranched C₁ -C₈ alkyl, aryl, preferably phenyl, or cyclohexyl;

or those of the formula D ##STR23## in which R₁₅ is hydrogen or a C₁ -C₄alkyl group, in particular CH₃, and p is from zero to 6, preferably fromzero to 2, especially zero.

Units which contain a bound photoinitiator are, in particular, those ofthe formula E ##STR24## in which BR is an --NH--CO.paren open-st.CH₂.paren close-st._(o) or ##STR25## bridge or a quaternary salt thereofwhich has the formula N ##STR26##

PI is the radical of a photoinitiator from the class consisting of thebenzoins, such as benzoin ethers, for example benzoin methyl ether,benzoin ethyl ether, benzoin isopropyl ether and benzoin phenyl ether,and benzoin acetate; acetophenones, such as acetophenone,2,2-dimethoxyacetophenone and 1,1 -dichloroacetophenone; benzil, benzilketals, such as benzil dimethyl ketal and benzil diethyl ketal;anthraquinones, such as 2-methylanthraquinone, 2-ethylanthraquinone,2-tert-butyl anthraquinone, 1-chloroanthraquinone and2-amylanthraquinone; furthermore benzophenones, such as benzophenone and4,4'-bis(N,N'-dimethylamino)benzophenone; thioxanthones and xanthones;acridine derivatives; phenazine derivatives; quinoxaline derivatives;and 1-aminophenyl ketones and in particular 1-hydroxyphenyl ketones, inparticular those of the formula ##STR27## in which X is --O--, --S-- or--N(R₁₂)--,

Y is a counterion, such as H₂ SO₄.sup.⊖, F.sup.⊖, Cl.sup.⊖, Br.sup.⊖,I.sup.⊖, CH₃ COO.sup.⊖, OH.sup.⊖, BF₄.sup.⊖ or H₂ PO₄.sup.⊖,

R₃ is hydrogen, a C₁ -C₆ alkyl group or a cycloalkyl group,

R₇ is hydrogen; unsubstituted or substituted, linear or branched C₁ -C₁₂alkyl; the

--(CH₂)_(r),--PI group or the --CO--R₁₃ group, in which R₁₃ is linear orbranched C₁ -C₆ alkyl which is unsubstituted or substituted by --COOH oracrylamide, or an unsubstituted, linear or branched radical of a C₃ -C₈olefin,

R₈ is hydrogen, or unsubstituted or substituted, linear or branched C₁-C₄ alkyl so long as R₇ is not --CO--R₁₃,

R₉ is unsubstituted or substituted, linear or branched C₁ -C₆ alkyl,unsubstituted or substituted, linear or branched C₁ -C₆ alkoxy, a6-membered carbocyclic or heterocyclic ring, or an unsubstituted linearor branched radical of a C₃ -C₈ olefin,

R₁₀ is a group of the formula --OR₁₄ or ##STR28## R₁₁, is unsubstitutedor substituted, linear or branched C₁ -C₆ alkyl, a 6-memberedcarbocyclic or heterocyclic ring, an unsubstituted, linear or branchedradical of a C₃ -C₈ olefin, or aryl, where

R₉ and R₁₁, together can also be cyclized to form a 5- or 6-memberedcarbocyclic ring,

R₁₂ is hydrogen or unsubstituted, linear or branched C₁ -C₄ alkyl,

R₁₄ is hydrogen or unsubstituted or substituted, linear or branched C₁C₄ alkyl,

R₁₅ and R₁₆, independently of one another, are unsubstituted, linear orbranched C₁ -C₄ alkyl, or R₁₅ and R₁₆ can be bonded together to form a5- or 6-membered heterocyclic ring,

m is 0 or 1,

n is a number from 1 to 12,

o is a number from 1 to 6, and

r is a number from 2 to 6,

where substituted radicals are substituted, in particular, by C₁ -C₄alkyl or by C₁ -C₄ alkoxy, with the following provisos:

if the BR bridge is a quaternary salt, n is a number from 2 to 12;

R₁₄ is not hydrogen if R₉ is a C₁ -C₆ alkoxy radical; and

R₇ is --CO--R₁₃ when n=1.

Examples of units containing basic groups are those of the formula F##STR29## in which R is a linear or branched bivalent radical of a C₁-C₁₂ alkane, and R₃ is hydrogen, a C₁ -C₆ alkyl group or a cycloalkylgroup, and R₇ is a basic primary, secondary or tertiary amino group, inparticular a secondary or tertiary amino group which is substituted byC₁ -C₆ alkyl, or a quaternary amino group of the formula

    --N⊕(R').sub.3 X⊖

in which R' is hydrogen or, independently of one another, a C₁ -C₁₂alkyl radical, in particular a C₁ -C₄ alkyl radical, and X is acounterion, for example HSO₄ .sup.⊖, F.sup.⊖, Cl.sup.⊖, Br.sup.⊖,I.sup.⊖, CH₃ COO.sup.⊖, OH.sup.⊖, BF.sup.⊖ or H₂ PO₄ .sup.⊖.

Examples of units containing acidic groups are those of the formula G##STR30## in which R and R₃ are as defined under the formula F, and R₈is the radical of a monobasic, dibasic or tribasic aliphatic oraromatic, saturated or unsaturated organic acid.

Examples of units containing crosslinkable groups bonded via urethane orfurther modifier groups bonded via urethane are those of the formula Hor J ##STR31## in which U is the ##STR32## or--Y--NH--CO--O--Z--O--CH═CH₂ group, X is a bridge having 2 to 12 carbonatoms, in particular an aliphatic, cycloaliphatic or aromatic bridge,especially alkylene, cyclohexylene or phenylene, which are unsubstitutedor in particular substituted by lower alkyl,

R₂ is hydrogen or a C₁ -C₄ alkyl group,

Y is a bridge having 7 to 12 carbon atoms with the same preferences asfor X,

Z is a C₂ --to C₁₂ alkylene bridge, which may be interrupted once ormore than once by oxygen atoms, and

A is an organic radical having 1 to 18 carbon atoms, in particular analiphatic, cycloaliphatic or aromatic radical, especially alkyl,cycloalkyl or phenyl, which are unsubstituted or in particularsubstituted by lower alkyl.

The novel crosslinkable polymer (prepolymer) is soluble in water.

The crosslinkable polymer (prepolymer) used in accordance with theinvention comprises the units containing one or more differentcrosslinkable group(s) and, if desired, the units containing the furthermodifier(s), reactive dye radicals and photoinitiators, etc, in a totalamount of from about 0.5 to 80%, preferably from 1 to 50%,advantageously from 1 to 25%, in particular from 2 to 15%, particularlypreferably from 2 to 10%, based on the number of functional groups inthe starting polymer, for example hydroxyl groups in the polyvinylalcohol.

Polymers (prepolymers) which can be crosslinked in accordance with theinvention and are intended for the production of contact lensescomprise, in particular, from about 0.5 to about 25%, in particular fromabout 1 to 15%, particularly preferably from about 2 to 12%, of theseunits.

Surprisingly, crosslinkable tinted polymers are extremely stable. Thisis unexpected to the person skilled in the art since higher-functionalacrylates, for example, usually require stabilization. If such compoundsare not stabilized, rapid polymerization occurs. However, spontaneouscrosslinking due to homopolymerization does not occur with the noveltinted, crosslinkable polymers. The crosslinkable tinted polymers can,in addition, be purified in a manner known per se, for example byprecipitation with acetone, dialysis or ultrafiltration, particularpreference being given to ultrafiltration. This purification operationallows the crosslinkable tinted polymers to be obtained in extremelypure form, for example as concentrated aqueous solutions, which are freeor at least substantially free from reaction products, such as salts,and starting materials, or other non-polymeric constituents. In the caseof ultrafiltration, the salts formed during neutralization of thereaction mixture and the salts present in the reactive dyes asimpurities, for example sodium sulfate and sodium chloride, are alsoremoved simultaneously.

The preferred method for the purification of the novel crosslinkabletinted polymers, ultrafiltration, which gives extremely pure products,can be carried out in a manner known per se. It is possible to carry outthe ultrafiltration repeatedly, for example from two to ten times.Alternatively, the ultrafiltration can also be carried out continuouslyuntil the desired degree of purity has been achieved. The desired degreeof purity can in principle be as great as desired. A suitable measure ofthe degree of purity is, for example, the GPC or the elemental analysis(for example chlorine content of the filtrate).

The novel tinted, high-purity, crosslinkable polymers can be crosslinkedin an extremely effective and targeted manner, in particular byphotochemical crosslinking.

The present invention therefore furthermore relates to aphotocrosslinked, tinted polymer which can be obtained byphotocrosslinking a crosslinkable, tinted polymer comprising covalentlybonded reactive dye radicals in the presence or absence of an additionalvinylic comonomer. These photocrosslinked, tinted polymers (hydrogels)are insoluble in water.

In the case of photochemical crosslinking (photocrosslinking), it isexpedient, especially where necessary, to add a photoinitiator which iscapable of initiating free-radical crosslinking. The crosslinking canthen be initiated by actinic or ionizing radiation.

The photocrosslinking is carried out in a suitable solvent. Suchsolvents are in principle all those which dissolve the crosslinkabletinted polymer and any vinylic comonomers additionally used.

The photocrosslinking is preferably carried out directly from an aqueoussolution of the novel water-soluble, crosslinkable tinted polymers,which can be obtained as a result of the preferred purification step,namely ultrafiltration, if desired after addition of an additionalvinylic comonomer.

The process for the preparation of the novel crosslinkable tintedpolymers comprises, for example, derivatizing a polymer backbone with acrosslinking agent, where the polymer backbone is still capable ofreacting covalently with a reactive dye, in particular a polyvinylalcohol polymer backbone, and photocrosslinking the derivatizedbackbone, in particular in essentially pure form, ie. for example, aftera single or repeated ultrafiltration, in particular in aqueous solution,in the presence or absence of an additional vinylic comonomer.

The vinylic comonomer which can additionally be used in thephotocrosslinking can be hydrophilic, hydrophobic or a mixture ofhydrophobic and hydrophilic vinylic monomers. Suitable vinylic monomersinclude, in particular, those which are usually used in the productionof contact lenses. The term "hydrophilic vinylic monomer" is taken tomean a monomer which, as a homopolymer, typically gives a polymer whichis soluble in water or is capable of absorbing at least 10% by weight ofwater. Analogously, the term "hydrophobic vinylic monomer" is taken tomean a monomer which, as a homopolymer, typically gives a polymer whichis insoluble in water or is capable of absorbing less than 10 per centby weight of water.

If a vinylic comonomer is used, the photocrosslinked tinted novelpolymers preferably comprise from about 1 to 15 per cent, particularlypreferably from about 3 to 8 per cent, of crosslinkable units, based,for example, on the number of hydroxyl groups of the polyvinyl alcohol,which are reacted with from about 0.1 to 80 units of the vinylicmonomer.

The proportion of vinylic comonomers, if used, is preferably from 0.5 to80 units per crosslinkable unit, in particular from 1 to 30 units ofvinylic comonomer per crosslinkable unit, particularly preferably from 5to 20 units per crosslinkable unit.

It is furthermore preferred to use a hydrophobic vinylic comonomer or amixture of a hydrophobic vinylic comonomer and a hydrophilic vinyliccomonomer which comprises at least 50 per cent by weight of ahydrophobic vinylic comonomer. This allows the mechanical properties ofthe photocrosslinked polymer to be improved without drastically reducingthe water content. However, both conventional hydrophobic vinyliccomonomers and conventional hydrophilic vinylic comonomers are inprinciple suitable for the copolymerization.

Suitable hydrophobic vinylic comonomers include, without this being acomprehensive list, C₁ -C₁₈ alkyl acrylates and methacrylates, C₃ -C₁₈alkylacrylamides and -methacrylamides, acrylonitrile, methacrylonitrile,vinyl C₁ -C₁₈ alkanoates, C₂ -C₁₈ alkenes, C₂ -C₁₈ haloalkenes, styrene,C₁ -C₆ alkylstyrene, vinyl alkyl ethers in which the alkyl moiety has 1to 6 carbon atoms, C2-C₁₀ perfluoroalkyl acrylates and methacrylates andcorrespondingly partially fluorinated acrylates and methacrylates, C₃-C₁₂ perfluoroalkyl ethylthiocarbonylaminoethyl acrylates and-methacrylates, acryloxy- and methacryloxyalkylsiloxanes,N-vinylcarbazole, C₁ -C₁₂ alkyl esters of maleic acid, fumaric acid,itaconic acid, mesaconic acid and the like. Preference is given to, forexample, C₁ -C₄ alkyl esters of vinylically unsaturated carboxylic acidshaving 3 to 5 carbon atoms or vinyl esters of carboxylic acids having upto 5 carbon atoms.

Examples of suitable hydrophobic vinylic comonomers include methylacrylate, ethyl acrylate, propyl acrylate, isopropyl acrylate,cyclohexyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethylmethacrylate, propyl methacrylate, vinyl acetate, vinyl propionate,vinyl butyrate, vinyl valerate, styrene, chloroprene, vinyl chloride,vinylidene chloride, acrylonitrile, 1-butene, butadiene,methacrylonitrile, vinyltoluene, vinyl ethyl ether,perfluorohexylethylthiocarbonylaminoethyl methacrylate, isobornylmethacrylate, trifluoroethyl methacrylate, hexafluoroisopropylmethacrylate, hexafluorobutyl methacrylate,tris(trimethylsilyloxy)silylpropyl methacrylate,3-methacryloxypropyl-pentamethyldisiloxane andbis(methacryloxypropyl)tetramethyldisiloxane.

Suitable hydrophilic vinylic comonomers include, without this being acomprehensive list, hydroxy-substituted lower alkyl acrylates andmethacrylates, acrylamide, methacrylamide, lower alkylacrylamides and-methacrylamides, methoxylated acrylates and methacrylates,hydroxy-substituted lower alkylacrylamides and -methacrylamides,hydroxy-substituted lower alkyl vinyl ethers, sodium ethylenesulfonate,sodium styrenesulfonate, 2-acrylamido-2-methylpropanesulfonic acid,N-vinylpyrrole, N-vinylsuccinimide, N-vinylpyrrolidone, 2- and4-vinylpyridine, acrylic acid, methacrylic acid, amino- (where the term"amino" also covers quatemary ammonium), mono(lower alkyl)amino- ordi(lower alkyl)amino(lower alkyl) acrylates and methacrylates allylalcohol and the like. Preference is given to, for example,hydroxy-substituted C2-C₄ alkyl (meth)acrylates, five-to seven-memberedN-vinyllactams, N,N-di-C₁ -C₄ alkyl(meth)acrylamides and vinylicallyunsaturated carboxylic acids having a total of 3 to 5 carbon atoms.

Examples of suitable hydrophilic vinylic comonomers include hydroxyethylmethacrylate, hydroxyethyl acrylate, acrylamide, methacrylamide,dimethylacrylamide, allyl alcohol, vinylpyridine, vinylpyrrolidone,glycerol methacrylate, N-(1,1-dimethyl-3-oxobutyl)acrylamide and thelike.

Preferred hydrophobic vinylic comonomers are methyl methacrylate andvinyl acetate.

Preferred hydrophilic vinylic comonomers are 2-hydroxyethylmethacrylate, N-vinylpyrrolidone and acrylamide.

The novel crosslinkable tinted homopolymers and copolymers can beconverted into mouldings, in particular contact lenses, in a mannerknown per se, for example by carrying out the crosslinking, inparticular photocrosslinking, in a suitable contact-lens mould. Theinvention therefore furthermore relates to mouldings essentiallycomprising a crosslinked tinted polymer made from a novel crosslinkabletinted polymer comprising units containing a crosslinkable group andunits containing a reactive dye radical. Further examples of novelmouldings, besides contact lenses, are biomedical mouldings andmouldings for specifically ophthalmic purposes, for example intraocularlenses, eye bandages, mouldings which can be used in surgery, such asheart valves, artificial arteries or the like, furthermore films andmembranes, for example membranes for diffusion control,photostructurable films for information storage, and photoresistmaterials, for example membranes and mouldings for etch resists andscreen printing resists.

A specific embodiment of the invention relates to contact lenses whichcomprise a novel tinted crosslinked polymer made from a crosslinkabletinted polymer or essentially comprising or consisting of a novelcrosslinked tinted polymer. Contact lenses of this type have a range ofunusual and extremely advantageous properties, including, for example,excellent compatibility with the human cornea, based on a balanced ratiobetween water content (about 50-90% by weight, in particular 60-85% byweight), high oxygen permeability and very good mechanical properties,for example softness (hydrogels), transparency, clarity, freedom fromstresses and tear strength. In addition, the novel tinted contact lenseshave high dimensional stability and have very homogeneous tinting orcolouring. Even after autoclaving one or more times at, for example,about 120° C. for about 30-40 minutes, no changes in shape are observed.If the novel tinted contact lenses are used as one-day lenses, theyadditionally require no care products. Furthermore, they areeconomically advantageous to produce. The tinted novel contact lensesare colour-fast to all types of sterilization treatment, such aschemical, enzymatic and heat sterilization.

It is furthermore emphasized that the novel tinted contact lenses can beproduced very simply, efficiently and quickly compared with the priorart. This is due to a number of factors. Firstly, the startingmaterials, such as the polymer backbones, are inexpensive to obtain orprepare. Secondly, it is advantageous that the crosslinkable polymersand the crosslinkable tinted polymers are surprisingly stable, so thatthey can be subjected to very substantial purification. The crosslinkingcan therefore be carried out using a crosslinkable tinted polymer whichrequires virtually no subsequent purification, such as, in particular,complex extraction of unpolymerized constituents. Furthermore, thecrosslinking can be carried out in purely aqueous solution, so that asubsequent hydration step is unnecessary. In addition, the reactiontimes during tinting of the polymers are very short. Finally, thephotocrosslinking takes place within less than 5 minutes, so that theprocess for the production of the novel tinted contact lenses can bedesigned to be extremely economical from this point of view too.

All the above advantages naturally apply not only to contact lenses, butalso to the other mouldings mentioned. The totality of the variousadvantageous aspects in the production of novel tinted mouldings resultsin the novel tinted mouldings being particularly suitable asmass-produced articles, for example as contact lenses, which are wornfor a short time span (from about 1 to 4 days) and are then replaced bynew lenses.

The present invention furthermore relates to the production of the noveltinted mouldings, in particular the novel tinted contact lenses. Theseprocesses are illustrated below using the example of contact lenses.However, these processes can also be used for the other mouldingsmentioned.

The novel tinted contact lenses can be produced in a manner known perse, for example in a conventional spin-casting mould, as described, forexample, in U.S. Pat. No. 3,408,429, or by the full-mould process in astatic mould, as described, for example, in U.S. Pat. No. 4 347 198.

It has been found that the process described above with reference tocrosslinkable tinted polymers comprising, in particular, units of theformula I is of general applicability. The present invention thereforealso relates to a novel process for the production of polymeric tintedmouldings, in particular tinted contact lenses, in which a water-solublecrosslinkable tinted polymer containing reactive dye radicals iscrosslinked in solution, and to mouldings, in particular contact lenses,obtainable by this process. The tinted mouldings obtainable bycrosslinking in this way are insoluble, but swellable, in water.

In detail, this process for the production of tinted mouldings, inparticular tinted contact lenses, comprises the following steps:

a) Preparation of an essentially aqueous solution of a water-solublecrosslinkable tinted polymer comprising units containing a crosslinkablegroup and units containing a bonded reactive dye radical,

b) introduction of the resultant solution into a mould,

c) initiation of the crosslinking in water or in an organic solvent inwhich the crosslinkable tinted polymer is dissolved, and

d) opening of the mould so that the moulding can be removed.

Unless expressly excluded below, the comments and preferences givenabove in connection with the crosslinkable tinted polymers comprisingunits of the formula I and the comments and preferences given inconnection with the processes for the preparation of polymers andproduction of mouldings, in particular contact lenses, from thesecrosslinkable tinted polymers also apply in connection with theabove-described process comprising steps a), b), c) and d). Thisstatement applies to all the cases in which the comments and preferencesin connection with crosslinkable tinted polymers comprising units of theformula I can be applied appropriately to the process described above.

The crucial criteria regarding whether a crosslinkable tinted polymercan be employed in the novel process are that the crosslinkable tintedpolymer comprises units containing a crosslinkable group and unitscontaining a bonded reactive dye radical, and that this polymer issoluble in water.

An essentially aqueous solution of a water-soluble crosslinkable tintedpolymer can be prepared in a manner known per se, for example byisolating the crosslinkable tinted polymer, for example in pure form,ie. free from undesired constituents, and dissolving the crosslinkabletinted polymer in an essentially aqueous medium.

The criterion that the crosslinkable tinted polymer is soluble in wateris, for the purposes of the invention, taken to mean in particular thatthe crosslinkable tinted polymer is soluble in an essentially aqueoussolution at 20° C. in a concentration of from about 3 to 90 per cent byweight, preferably from about 5 to 60 per cent by weight, in particularfrom about 10 to 60 per cent by weight. If possible in individual cases,crosslinkable tinted polymer concentrations of greater than 90% are alsoincluded for the purposes of the invention. Particular preference isgiven to crosslinkable tinted polymer concentrations in solution of fromabout 15 to about 50 per cent by weight, in particular from about 15 toabout 40 per cent by weight, for example from about 25 to about 40 percent by weight.

For the purposes of this invention, essentially aqueous solutions of thecrosslinkable tinted polymer include in particular solutions in water,in aqueous salt solutions, in particular in aqueous salt solutionshaving an osmolarity of from about 200 to 450 milliosmol in 1000 ml(unit: mOsm/l), preferably an osmolarity of from about 250 to 350mOsm/l, in particular about 300 mOsm/l, or in mixtures of water oraqueous salt solutions with physiologically acceptable polar organicsolvents, for example glycerol. Preference is given to solutions of thecrosslinkable tinted polymers in water alone.

The aqueous salt solutions are advantageously solutions ofphysiologically acceptable salts, such as buffer salts, for examplephosphate salts, which are conventional in the area of contact-lenscare, or isotonicizing agents, in particular alkali metal halides, forexample sodium chloride, which are conventional in the area ofcontact-lens care, or solutions of mixtures thereof. An example of aparticularly suitable salt solution is an artificial, preferablybuffered tear fluid whose pH and osmolarity have been matched to naturaltear fluid, for example an unbuffered, preferably buffered for exampleby phosphate buffer, sodium chloride solution whose osmolarity and pHconform to the osmolarity and pH of human tear fluid.

The above-defined, essentially aqueous solutions of the crosslinkabletinted polymer are preferably pure solutions, ie. those which are freeor essentially free from undesired constituents. Particular preferenceis given to solutions of the crosslinkable tinted polymer in pure wateror in an artificial tear fluid as described above.

The viscosity of the solution of the crosslinkable tinted polymer in theessentially aqueous solution is unimportant over broad limits. However,it should preferably be a flowable solution which can be shaped withoutstresses.

The molecular weight of the crosslinkable tinted polymer is likewiseunimportant within broad limits. However, the crosslinkable tintedpolymer preferably has a molecular weight of from about 10,000 to about200,000.

The crosslinkable tinted polymer used in accordance with the inventionshould furthermore, as mentioned, comprise crosslinkable groups. Theterm crosslinkable groups is taken to mean, in addition to the acetalgroups mentioned at the outset containing crosslinkable groups, allconventional crosslinkable groups known to the person skilled in theart, for example photocrosslinkable or thermally crosslinkable groups .Particularly suitable crosslinkable groups are those as already proposedunder the production of contact-lens materials. These include, inparticular, but not exclusively, groups which contain carbon-carbondouble bonds. In order to demonstrate the variety of crosslinkablegroups which are suitable, crosslinking mechanisms which may bementioned here, merely by way of example, are free-radicalpolymerization, 2+2 cycloaddition, Diels-Alder reaction, ROMP (ringopening metathesis polymerization), vulcanization, cationic crosslinkingand epoxy curing.

Suitable polymeric backbones, in addition to the starting polymersalready mentioned at the outset, are materials as have in some casesalready been proposed as contact-lens materials and which are capable ofcovalently binding reactive dyes, for example polymeric diols other thanPVA, polymers comprising saccharides, polymers comprisingvinylpyrrolidone, polymers comprising alkyl (meth)acrylates, polymerscomprising alkyl (meth)acrylates which are substituted by hydrophilicgroups, such as hydroxyl, carboxyl or amino groups, polyalkyleneglycols, or copolymers or mixtures thereof.

As already mentioned, for a crosslinkable tinted polymer to be suitablein the novel process, it is essential that it is crosslinkable. However,the crosslinkable polymer is uncrosslinked so that it is water-soluble.

Furthermore, the crosslinkable polymer and the crosslinkable tintedpolymer are advantageously stable in the uncrosslinked state, so thatthey can be subjected to purification, as described above. Thecrosslinkable tinted polymers are preferably employed in thecrosslinking process in the form of pure solutions. The crosslinkabletinted polymers can be converted into the form of pure solutions asdescribed below, for example.

The water-soluble, crosslinkable tinted polymers used in the novelprocess can preferably be purified in a manner known per se, for exampleby precipitation with organic solvents, such as acetone, filtration andwashing, extraction in a suitable solvent, dialysis or ultrafiltration,particular preference being given to ultrafiltration. This purificationoperation allows the crosslinkable tinted polymers to be obtained inextremely pure form, for example as concentrated aqueous solutions,which are referred to hereinafter as pure or essentially pure. This termis understood to refer to a crosslinkable polymer or to a solutionthereof which is free or at least substantially free from undesiredconstituents.

Undesired constituents in this context are generally all constituentswhich are physiologically undesired, especially monomeric, oligomeric orpolymeric starting compounds used for the preparation of thewater-soluble, crosslinkable tinted polymer, or byproducts formed duringthe preparation of the water-soluble, crosslinkable tinted polymer.Preferred degrees of purity of these constituents are less than 0.01%,in particular less than 0.001%, very particularly preferably less than0.0001% (1 ppm). It is to be noted, however, that there may be presentin the solution, for example by formation as byproducts during thepreparation of the water-soluble, crosslinkable tinted polymer,constituents which are not undesired from a physiological point of view,such as for example sodium chloride. Preferred degrees of purity ofthese constituents are less than 1%, in particular less than 0.1%, veryparticularly preferably less than 0.01%. In most cases such levels ofconstituents may be obtained by applying 3 to 4 repeated ultrafiltrationcycles.

The preferred process for the purification of the crosslinkable tintedpolymers used in the crosslinking process, namely ultrafiltration, canbe carried out in a manner known per se. The ultrafiltration can becarried out repeatedly, for example from two to ten times.Alternatively, the ultrafiltration can also be carried out continuouslyuntil the desired degree of purity has been achieved. The desired degreeof purity can in principle be chosen to be as great as desired.

In a preferred embodiment of the process for the production of tintedcontact lenses, an essentially aqueous solution of the crosslinkabletinted polymer which is essentially free from undesired constituents,for example free from monomeric, oligomeric or polymeric startingcompounds used for the preparation of the crosslinkable tinted polymer,and/or free from by-products formed during the preparation of thecrosslinkable tinted polymer, is prepared in step a) and used further.This essentially aqueous solution is particularly preferably a purelyaqueous solution or a solution in an artificial tear fluid as describedabove. It is furthermore preferred for the process to be carried outwithout addition of a comonomer, for example a vinylic comonomer.

Owing to the abovementioned measures and in particular owing to acombination of said measures, the crosslinking process is carried outusing a solution of the crosslinkable tinted polymer containing no oressentially no undesired constituents requiring extraction aftercrosslinking. It is therefore a particular feature of this preferredembodiment of the process that extraction of undesired constituents isnot necessary after the crosslinking.

The crosslinking process is therefore preferably carried out in such away that the essentially aqueous solution of the crosslinkable tintedpolymer is free or essentially free from undesired constituents, inparticular from monomeric, oligomeric or polymeric starting compoundsused for the preparation of the crosslinkable tinted polymer, or fromby-products formed during the preparation of the crosslinkable tintedpolymer, and/or that the solution is used without addition of acomonomer.

An addition which may be added to the solution of the crosslinkabletinted polymer (or a mixture of such polymers) is a photoinitiator forthe crosslinking so long as an initiator is necessary for crosslinking.This may be the case, in particular, if the crosslinking takes place byphotocrosslinking, which is preferred in the novel process.

If, however, the crosslinkable tinted polymer comprises units containinga photoinitiator component, the crosslinking can be carried out directlywithout addition of an additional photo initiator.

In the case of photocrosslinking, it is expedient to add an initiatorwhich is capable of initiating free-radical crosslinking and is readilysoluble in water. Examples thereof are known to the person skilled inthe art; suitable photoinitiators which may be mentioned specificallyare benzoins, such as benzoin, benzoin ethers, such as benzoin methylether, benzoin ethyl ether, benzoin isopropyl ether and benzoin phenylether, and benzoin acetate; acetophenones, such as acetophenone,2,2-dimethoxyacetophenone and 1,1-di-chloroacetophenone; benzil, benzilketals, such as benzil dimethyl ketal and benzil diethyl ketal,anthraquinones, such as 2-methylanthraquinone, 2-ethylanthraquinone,2-tert-butyl-anthraquinone, 1-chloroanthraquinone and2-amylanthraquinone; furthermore triphenyl-phosphine, benzoylphosphineoxides, for example 2,4,6-trimethylbenzoyldiphenylphos-phine oxide,benzophenones, such as benzophenone and4,4'-bis(N,N'-dimethylamino)-benzophenone; thioxanthones and xanthones;acridine derivatives; phenazine derivatives; quinoxaline derivatives and1-phenyl-1,2-propanedione 2-0-benzoyl oxime; 1-amino-phenyl ketones and1-hydroxyphenyl ketones, such as 1-hydroxycyclohexylphenyl ketone,phenyl 1-hydroxyisopropyl ketone, 4-isopropylphenyl 1-hydroxyisopropylketone, 2-hydroxy- 1- 4-(2-hydroxyethoxy)phenyl!-2-methylpropan- 1-one,1-phenyl-2-hydroxy-2-methylpropan-1-one, and2,2-dimethoxy-1,2-diphenylethanone, all of which are known compounds.

Particularly suitable photoinitiators, which are usually used incombination with UV lamps as light source, are acetophenones, such as2,2-dialkoxybenzophenones and hydroxyphenyl ketones, for example theinitiators obtainable under the trade names Irgacure® 2959 and Irgacure®81173.

Another class of photoinitiators usually employed when argon ion lasersare used are benzil ketals, for example benzil dimethyl ketal.

The photoinitiators are added in effective amounts, expediently inamounts of from about 0.1 to about 2.0% by weight, in particular from0.2 to 0.5% by weight, based on the total amount of the crosslinkabletinted polymer.

The resultant solution can be introduced into a mould using methodsknown per se, such as, in particular, conventional metering, for exampledropwise. The novel tinted contact lenses can be produced in a mannerknown per se, for example in a conventional spin-casting mould, asdescribed, for example, in U.S. Pat. No. 3,408,429, or by the full-mouldprocess in a static mould, as described, for example, in U.S. Pat. No.4,347,198. Appropriate moulds are made, for example, of polypropylene.Examples of suitable materials for reusable moulds are quartz andsapphire glass.

The novel crosslinkable tinted polymers which are suitable can becrosslinked by irradiation with ionizing or actinic radiation, forexample electron beams, X-rays, UV or VIS light, ie. electromagneticradiation or particle radiation having a wavelength in the range fromabout 250 to 650 nm. Also suitable are He/Cd, argon or nitrogen or metalvapour or NdYAG laser beams with multiplied frequency. It is known tothe person skilled in the art that each selected light source requiresselection and, if necessary, sensitization of the suitablephotoinitiator. It has been recognized that in most cases the depth ofpenetration of the radiation into the crosslinkable polymer and the rateare in direct correlation with the absorption coefficient andconcentration of the photoinitiator.

The crosslinking can, if desired, also be initiated thermally. It shouldbe emphasized that the crosslinking can take place in a very short timein accordance with the invention, for example in less than five minutes,preferably in less than one minute, in particular in up to 30 seconds,particularly preferably as described in the examples.

Apart from water, which is preferred, the crosslinking medium canadditionally be any medium in which the crosslinkable tinted polymer issoluble. In the case of polyvinyl alcohol as the polymer backbone, forexample, all solvents which dissolve polyvinyl alcohol are suitable,such as alcohols, for example glycols, glycerol, piperazine (at elevatedtemperature), diamines, such as triethylenediamine, formamide,dimethylformamide, hexamethylphosphoric triamide, dimethyl sulfoxide,pyridine, acetonitrile and dioxane.

The opening of the mould so that the moulding can be removed can becarried out in a manner known per se. Whereas the process proposed inthe prior art (U.S. Pat. No. 3,408,429 and 4,347,198) requiressubsequent purification steps at this point, for example by extraction,and also steps for hydration of the resultant mouldings, in particularcontact lenses, such steps are unnecessary here.

Since the solution of the crosslinkable tinted polymer preferablycomprises no undesired low-molecular-weight constituents, thecrosslinked tinted product also comprises no such constituents.Subsequent extraction is therefore unnecessary. Since the crosslinkingis carried out in an essentially aqueous solution, subsequent hydrationis unnecessary. These two advantages mean, inter alia, that complexsubsequent treatment of the resultant tinted mouldings, in particularcontact lenses, is unnecessary. The tinted contact lenses obtainable bythe novel process are therefore distinguished, in an advantageousembodiment, by the fact that they are suitable for their intended usewithout extraction. The term `intended use` in this connection is takento mean, in particular, that the contact lenses can be employed in thehuman eye. The contact lenses obtainable by the crosslinking process arefurthermore distinguished in an advantageous embodiment by the fact thatthey are suitable for their intended use without hydration.

This process therefore proves to be extremely suitable for the efficientproduction of a large number of mouldings, such as contact lenses, in ashort time. The tinted contact lenses obtainable by this process have,inter alia, the advantages over the contact lenses known from the priorart that they can be used as intended without subsequent treatmentsteps, such as extraction or hydration. In addition, virtually anydesired shade or any tint can be achieved by using a specific reactivedye or a combination of reactive dyes. Bleeding of the dye does notoccur, nor does leaching out, neither in the tear fluid nor in thesterilization solution.

The examples below serve to further illustrate the invention. In theexamples, unless expressly stated otherwise, amounts are by weight andtemperatures are given in degrees Celsius. RT denotes room temperatureof about 20° C. These examples are not intended to represent anyrestriction of the invention, for example to the scope of the examples.

EXAMPLE 1

220 g (5.5 mol) of sodium hydroxide are dissolved in 300 g of water and700 g of ice in a 3 liter reactor fitted with stirrer and cooling means.The sodium hydroxide solution is cooled to 10° C., and 526 g (5.0 mol)of aminoacetaldehyde dimethyl acetal and 50 mg of4-hydroxy-2,2,6,6-tetramethylpiperidine 1-oxide (free-radical inhibitor)are added. 548.6 g (5.5 mol) of methacryloyl chloride are slowly addedto this solution at 10° C. over the course of 3.5 hours. When theaddition is complete, the pH slowly drops to 7.2, and amine is no longerdetectable by GC. The reaction mixture is extracted with 500 ml ofpetroleum ether in order to remove impurities, and the water phase issaturated with sodium chloride and extracted three times with 500 ml oftert-butyl methyl ether. The organic phase is dried using magnesiumsulfate, filtered and evaporated on a rotary evaporator. The 882.2 g ofyellowish oil obtained are slowly stirred into 2000 ml of petroleumether at -10° C. using an Ultraturax. The product crystallizes, and isfiltered off and dried, giving 713.8 g of methacrylamidoacetaldehydedimethyl acetal (86% of theory), melting point 30-32° C. The product is99.7% pure according to GC.

EXAMPLE 2

General method for the preparation of high-acetate products; of thereaction of PVA with acetals or aldehydes.

300 g of a PVA (Mowiol 4-88, unless stated otherwise) are introducedinto a 2 liter twin-jacket reactor fitted with stirrer and thermometer,800 g of demineralized water are added, and the mixture is warmed to 95°C. with stirring. After one hour, all the reactants have dissolved togive a clear solution, which is cooled to 20° C. 27 g (0.155 mol) ofmethacrylamidoacetaldehyde dimethyl acetal (from Example 1), 440 g ofacetic acid, 100 g of conc. hydrochloric acid (37%) and sufficientdemineralized water to give a total of 200 g of reaction solution areadded. The mixture is stirred at 20° C. for 20 hours.

Isolation can be carried out by ultrafiltration: the reaction mixture iscooled to 15° C. and the pH is adjusted to 3.6 by means of aqueous NaOH(5%). The polymer solution is filtered through a 0.45 μm filter andpurified by ultrafiltration. The ultrafiltration is carried out using a1 KD Omega membrane from Filtron. The ultrafiltration is continued to aresidual sodium chloride content of 0.004%. Before the purification iscompleted, the solution is adjusted to pH =7 using 0.1N sodium hydroxidesolution. Concentration gives 1995 g of a crosslinkable 14.54% polymersolution (92% of theory); N content (Kjeldahl determination) =0.683%,acetate content (determined by hydrolysis) =2.34 meq/g, intrinsicviscosity =0.310, 0.5 meq/g of double bonds (determined bymicrohydrogenation), 15.3 meq/g of free hydroxyl groups (determined byre-acetylation), GPC analysis (in water): M_(w) =19,101, M_(n) =7522,M_(w) /M_(n) =2.54.

The isolation can also be carried out by precipitation: the reactionmixture is adjusted to pH 3.6 by means of triethylamine and precipitatedin acetone in a ratio of 1:10. The precipitate is separated off,dispersed twice in ethanol and once in acetone and dried. The resultantproduct has the same properties as that obtained above byultrafiltration.

EXAMPLE 3

General procedure for the acid hydrolysis of VP-VAc polymers. LuviskolVA (BASF) or VP-VAc copolymer (Aldrich) comprising from 18 to 70 percentby weight of VP is introduced as a 10 percent by weight solution inmethanol or in methanol/water (10-90% of water). An equimolar amount ofacid, namely conc. sulfuric acid (95%), conc. hydrochloric acid (37%) orhighly acidic ion exchanger, corresponding to the VAc content is added,and the mixture is then heated to the reflux temperature. The course ofthe reaction is monitored by periodic sampling and titration with 0.1NKOH solution (for example Mettler DL 40 titrator) (determination of theconcentration of the acetic acid formed). The hydrolysis is terminatedeither when the desired degree of hydrolysis has been reached or thehydrolysis is complete (concentration of the acetic acid reaches aconstant value). For complete hydrolysis, a reaction time of 1-2 days isrequired. Complete hydrolysis does not necessarily mean that all thehydrolysable ester groups have been removed, but instead that thehydrolysis has ceased. The methanolic reaction solution is subsequentlypassed through a column containing basic ion exchanger which has beenwashed neutral (Merck; 1.2 molar with respect to the acid employed) inorder to remove the acetic acid, and is evaporated on a rotaryevaporator. The evaporated solution is sheeted out and dried in air fora few days and then at 40° C. and 0.1 mbar (10 Pa) to constant weight.Alternatively, the evaporated solution can be diluted with water andfreed from residual alcohol in a rotary evaporator; the aqueous solutionremaining is then spray-dried. The resultant starting polymers arereadily soluble in water, alcohols (lower alkanols), dimethylformamide(DMF), N,N-dimethylacetamide (DMA) and dimethyl sulfoxide (DMSO).

EXAMPLE 4

In each case, 30 ml of a 14 percent by weight PVA solution from Example2 are stirred for 1 minute with various volumes (V) as shown in Table 1of 0.5 percent by weight sodium carbonate solution. 60 mg of aDuasyn-Rot R-F3B solution are added in each case, and the mixtures arestirred for 2 minutes at RT while the pH is monitored. The calculatedamount of 0.01N HCl solution for neutralization is then added.Thin-layer chromatography (TLC; stationary phase silica gel 60 F₂₅₄ onaluminium foil, layer thickness 0.2 mm; Merck) in acetone shows nounbound dye. The mixture is subjected to ultrafiltration through a 3 kDmembrane (Filtron) in an ultrafiltration cell (Berghof) until chlorideis no longer detectable by argentometry. The concentration of thesolution can likewise be carried out in the ultrafiltration cell or byvacuum distillation (140 mbar, 40° C.) with blowing-in of air, or thesolution freed from salts is precipitated in acetone and the resultantsolid is dried in vacuo.

                  TABLE 1    ______________________________________         V (sodium pH before                            pH after                                  V (hydro-                                         pH after addition         carbonate)/                   addition addition                                  chloric                                         of hydrochloric    Ex.  ml        of dye   of dye                                  acid)/ml                                         acid    ______________________________________    4a)  10        10.8     10.6  50     6.5    4b)  5         10.7     10.5  20     6.8    4c)  1         9.1      8.5   4      6.4    4d)  0.5       6.4      6.4   1.5    5.9    ______________________________________

EXAMPLE 5

A mixture of 15 ml of a 30 percent by weight aqueous solution ofpolyethyleneimine (Polysciences) and 15 ml of demineralized water (pH ofthe mixture: 10.5) is adjusted to a pH of 6.8 using 3 ml of 37%hydrochloric acid. 5 ml of 0.5 percent sodium carbonate solution (pH7.2) are added, followed by 60 mg of a Duasyn-Blau R-R solution (pH7.4), and the pH is adjusted to 7.2 by means of 20 ml of 0.01Nhydrochloric acid. TLC in acetone shows no unbound dye.

EXAMPLE 6

A solution of 3.00 g of a terpolymer of vinylpyrrolidone (43.4 percentby weight), vinyl acetate (25.2 percent by weight) and vinyl alcohol(31.4 percent by weight) prepared as described in Example 3 (preparedfrom Luviskol VA 37 HM (BASF)) in 60 ml of demineralized water (pH 8.3)is stirred for 1 minute with 5 ml of 0.5 percent sodium carbonatesolution (pH 10.8). 40 mg of a Duasyn-Blau R-KG solution (pH 10.8) areadded, and the mixture is stirred for 2 minutes. After addition of 30 mlof 0.01N hydrochloric acid, the pH is 6.5. TLC shows no unbound dye.

EXAMPLE 7

In each case, 30 ml of a 14 percent by weight crosslinkable PVA solutionas per Example 2 (with the acetal from Example 1) are stirred for 1minute with 5 ml of demineralized water and 5 ml of a 0.5 percent sodiumcarbonate solution, and a dye as shown in Table 2, dissolved in 1 ml ofdemineralized water, is then added. After a reaction time of 8 minutes,during which a sample is taken every minute for TLC and the pH slowlydrops somewhat, the mixture is neutralized by means of 20 ml of 0.01Nhydrochloric acid. TLC in acetone shows no free dye.

                  TABLE 2    ______________________________________                                           pH after                            pH before                                   pH after a                                           addition of                   Amount of                            addition                                   reaction time                                           the hydro-    Ex.  Dye       dye/mg   of dye of 8 minutes                                           chloric acid    ______________________________________    7a)  Duasyn-Gelb                   60       10.6   9.9     6.2         R-Gl    7b)  Duasyn-Rot                   60       10.6   10.1    6.4         R-F3B    7c)  Duasyn-Blau                   30       10.6   10.0    6.4         R-KG    7d)  Duasyn-   30       10.6   10.3    6.7         Grun R-K6B    7e)  Duasyn-   45       10.7   10.2    6.6         Schwarz         R-KRL    7f)  Duasyn-   30       10.6   10.2    6.5         Schwarz         R-N    7g)  Remazol   15       10.8   10.2    6.5         Brillantblau         B    7h)  Remazol   15       10.5   10.2    6.5         Brillantblau         BB    7i)  Remazol   15       10.8   10.2    6.6         Druck-         schwarz G    ______________________________________

EXAMPLE 8

In each case, 30 ml of a 15 percent by weight solution of Mowiol 4-88(PVA from Hoechst AG) are stirred for 1 minute with 5 ml ofdemineralized water and 5 ml of a 0.5 percent sodium carbonate solution,and, at room temperature, a solution of 15 mg of a dye as shown in Table3 in 1 ml of water are added. The conversion is monitored by samplingfor TLC in acetone.

                  TABLE 3    ______________________________________    Ex.    Dye             TLC results    ______________________________________    8a)    Remazol Brillantblau B                           no free dye detectable    8b)    Remazol Brillantblau BB                           no free dye detectable    8c)    Remazol Schwarz B                           no free dye detectable after 3                           minutes    ______________________________________

EXAMPLE 9

Batches as in Example 8, reaction temperature 50° C.: dyes as shown inTable 4.

                  TABLE 4    ______________________________________    Ex.  Dye              TLC results    ______________________________________    9a)  Remazol Brillantblau B                          no free dye detectable    9b)  Remazol Brillantblau BB                          no free dye detectable    9c)  Remazol Brillantblau R                          no free dye detectable after a                          reaction time of 1-2 minutes    9d)  Remazol Brillantblau R spez.                          no free dye detectable after a                          reaction time of 1-2 minutes    9e)  Remazol Gelb GR  no free dye detectable after a                          reaction time of 3 minutes    ______________________________________

EXAMPLE 10

50 ml of a 14 percent by weight crosslinkable PVA solution as perExample 2 (with the acetal from Example 1) (pH 6.2) are stirred for 1minute with 8 ml of a 0.5 percent sodium carbonate solution (pH 10.8)and then for 3 minutes with a solution of 50 mg of Duasyn-Blau R-KG in 1ml of water (pH 10.7 after 1 minute; pH 10.6 after 2 minutes). Afterthis time, the mixture is neutralized (pH 7.0) by means of 30 ml of0.01N hydrochloric acid. TLC in acetone shows no free dye. The solutionis made up to 400 ml twice and subjected to ultrafiltration through a 3kD membrane (Filtron) in an ultrafiltration cell (Berghof) until nochloride can be detected by argentometry. A further concentration to 33percent by weight is carried out by vacuum distillation (140 mbar, 40°C.) and blowing-in of air.

EXAMPLE 11

50 ml of a 14 percent by weight crosslinkable PVA solution as perExample 2 (with the acetal from Example 1) (pH 6.44) are stirred for 1minute with 8 ml of a 0.5 percent sodium carbonate solution (pH 10.84)and then for 4 minutes with a solution of 100 mg of Duasyn-Rot R-F3B in1 ml of water (pH 10.6 after 1 minute; pH 10.5 after 2 minutes; pH 10.4after 3 minutes). After this time, the mixture is neutralized (pH 6.8)by means of 30 ml of 0.01N hydrochloric acid. TLC in acetone shows nofree dye. The solution is made up to 400 ml and subjected toultrafiltration through a 3 kD membrane (Filtron) in an ultrafiltrationcell (Berghof). The mixture is again made up with 400 ml of water, afterwhich chloride is no longer detectable by argentometry, and the mixtureis concentrated to 31% by weight.

EXAMPLE 12

200 g of a 14 percent by weight crosslinkable PVA solution as perExample 2 (with the acetal from Example 1) (pH 6.2) are stirred with 30ml of 0.5 percent sodium carbonate solution (pH 10.94 after 1 minute). Asolution of 100 mg of Remazol Schwarz B in 5 ml of water is added, andthe mixture is stirred for 12 minutes. During this period, the pH dropscontinuously from 10.7 (after 1 minute) to 10.2 (after 12 minutes).After only 1 minute, TLC in acetone shows no free dye. Afterneutralization (pH 7.0) by means of 1 ml of 1N hydrochloric acid, thebatch is mixed with 150 g of water and introduced into anultrafiltration cell (Berghof) and subjected to ultrafiltration througha 3 kD membrane (Filtron), and washed with a total of 450 ml of wateruntil the sodium chloride content in the eluate is 0.003 percent byweight (determined by argentometry). Further concentration of thesolution to 37 percent by weight is carried out by removal of water bydistillation at 140 mbar and 40° C. with blowing-in of air.

EXAMPLE 13

22 percent by weight aqueous solutions of dyes as shown in Table 5 arereacted at room temperature with solutions of aminoacetaldehyde dimethylacetal (Aldrich) in 2 g of water. The reaction is monitored by TLC inacetone. No free dye is detectable.

                  TABLE 5    ______________________________________                      Initial  Initial                                      Initial weight of                      weight of                               weight of                                      aminoacetaldehyde    Ex.  Dye          dye/g    water/g                                      dimethyl acetal/g    ______________________________________    12a) Remazol Schwarz B                      4        14     0.951    12b) Remazol Brillant-                      4        14     0.886         blau R    12c) Duasyn-Blau R-KG                      8        10     0.563    12d) Remazol Gold-                      4        14     0.858         orange 3G    12e) Duasyn-Rot R-F3B                      16        2     0.808    12f) Remazol Gelb GR                      4        14     0.772    ______________________________________

EXAMPLE 14

Analogously to Example 2, 400 g of PVA (Mowiol 4-88) are stirred for 24hours at 20° C. with 40 g of methacrylamidoacetaldehyde dimethyl acetal,7 g of 4-aminobutyraldehyde diethyl acetal, 266.6 g of conc.hydrochloric acid (37%), 666.6 g of acetic acid and 2666.6 g of water.The pH is adjusted to 3.6 by means of aqueous NaOH, the mixture issubjected to ultrafiltration through a 5 kD membrane and then adjustedto pH 7. Concentration gives a 15.62% crosslinkable polymer solutionhaving an amine content of 0.1 mmol/g, an acetate content of 2.383mmol/g and an intrinsic viscosity of 0.339.

EXAMPLE 15

200 g of a 16 percent by weight PVA solution as per Example 14 arediluted with 100 g of water, and a solution of 50 mg of Remazol Gelb GRin 2.5 ml of water is slowly added with vigorous stirring. TLC inacetone shows no free dye. The solution is transferred to anultrafiltration cell (Berghof) and, after making up to 400 ml withwater, subjected to ultrafiltration through a 3 kD membrane. The mixtureis made up with 200 ml of water and then concentrated to a solidscontent of 16 percent by weight. Argentometry shows that the saltcontent of the eluate is 0.003 percent by weight. Further concentrationto 36 percent by weight is carried out by vacuum distillation (140 mbar,40° C.) with blowing-in of air.

EXAMPLE 16

200 g of a 16 percent by weight PVA solution as per Example 14 arediluted with 100 g of water, and a solution of 50 mg of RemazolGoldorange 3G in 2.5 ml of water is slowly added with vigorous stirring.TLC in acetone shows no free dye. The solution is transferred to anultrafiltration cell (Berghof) and, after making up to 400 ml withwater, subjected to ultrafiltration through a 3 kD membrane. The mixtureis made up with 250 ml of water and then concentrated to a solidscontent of 20 percent by weight. Argentometry shows that the saltcontent of the eluate is 0.003 percent by weight. Further concentrationto 34 percent by weight is carried out by vacuum distillation (140 mbar,40° C.) with blowing-in of air.

EXAMPLE 17

13.987 g of the crosslinkable PVA solution from Example 10 coloured bymeans of Duasyn-Blau R-KG are stirred with a solution of 13.9 g ofIrgacure 2959 (0.3% based on the polymer) in 0.626 ml of water. Theresulting 30 percent PVA solution is transferred into quartz moulds andirradiated for from 5 to 10 seconds with intense UV light (UVA PRINT 300CM with H-lamp from Honle, 3200 W, 12 mW/cm², measured with a Honle-UV-Bdetector in the wavelength range from 280 to 320 nm) and crosslinked togive a tinted hydrogel. Extraction experiments on 20 lenses in 10 ml ofwater (1 hour at 121° C.) show that, according to the UV-VIS spectrum ofthe extraction solution, no coloured polymer is extracted from thelenses (the detection limit of the dye by means of the UV-VIS spectrumis approx. 1 ppm).

EXAMPLE 18

A mixture of 1.475 g of a coloured sol as in Example 17 and 1.474 g of aPVA sol comprising crosslinkable PVA (cf. Example 2) and 0.3 percent byweight of Irgacure 2959 is introduced into moulds and crosslinked asdescribed in Example 17 to give a coloured hydrogel.

EXAMPLE 19

5.166 g of a PVA solution as described in Example 11 which has beencoloured with Duasyn-Rot R-F3B are stirred with a solution of 4.8 mg ofIrgacure 2959 (0.3% by weight based on the polymer) in 189 mg of water.After the PVA solution has been transferred into moulds and irradiatedwith UV light, crosslinking is carried out as described in Example 17 togive a coloured hydrogel.

EXAMPLE 20

3.973 g of a PVA solution as described in Example 12 which has beencoloured with Remazol Schwarz B are stirred with a solution of 4.4 mg ofIrgacure 2959 (0.3% by weight based on the polymer) in 961 mg of water.After the PVA solution has been transferred into moulds and irradiatedwith UV light, crosslinking is carried out as described in Example 17 togive a coloured hydrogel.

EXAMPLE 21

A mixture of 1.193 g of a coloured sol as in Example 20 and 1.165 g of aPVA sol comprising crosslinkable PVA (cf. Example 2) and 0.3 percent byweight of Irgacure 2959 is introduced into moulds and crosslinked asdescribed in Example 17 to give a coloured hydrogel.

EXAMPLE 22

A mixture of 1.292 g of a coloured sol as in Example 19 and 1.236 g of aPVA sol comprising crosslinkable PVA (cf. Example 2) and 0.3 percent byweight of Irgacure 2959 is introduced into moulds and crosslinked asdescribed in Example 17 to give a coloured hydrogel.

EXAMPLE 23

7.937 g of a PVA solution as described in Example 15 which has beencoloured with Remazol Gelb GR are stirred with a solution of 8.6 mg ofIrgacure 2959 (0.3% by weight based on the polymer) in 1.651 g of water,transferred into moulds and crosslinked as described in Example 17 togive a coloured hydrogel.

EXAMPLE 24

6.530 g of a PVA solution as described in Example 16 which has beencoloured with Remazol Goldorange 3G are stirred with a solution of 6.6mg of Irgacure 2959 (0.3% by weight based on the polymer) in 0.815 g ofwater, transferred into moulds and crosslinked as described in Example17 to give a coloured hydrogel.

EXAMPLE 25

5.753 g of a PVA solution as described in Example 12 which has beencoloured with Remazol Schwarz B are stirred with a solution of 10.7 mgof Irgacure 2959 (0.5% by weight based on the polymer) in 1.400 g ofwater, transferred into moulds and crosslinked as described in Example17 to give a coloured hydrogel.

EXAMPLE 26

7.002 g of a PVA solution as described in Example 12 which has beencoloured with Remazol Schwarz B are stirred with a solution of 26.1 mgof Irgacure 2959 (1.0% by weight based on the polymer) in 1.704 g ofwater, transferred into moulds and crosslinked as described in Example17 to give a coloured hydrogel.

Table 6 below shows the water content, the transmission, the wavelengthand the central thickness of the contact lenses produced in Examples 17to 26.

                  TABLE 6    ______________________________________        Water content                    Transmission                              Wavelength                                       Central thickness    Ex. a)  %!      b)  %!     mm!      μm!    ______________________________________    17  65          62        672      105    18  66          74        672      95    19  66          78        553      83    20  65          65        592      100    21  65          90        596      65    22  66          86        553      91    25  66          66        592      95    26  65          64        592      105    ______________________________________     a) ±2%     b) ±5%

EXAMPLE 27

(Comparative example--untinted lenses) A PVA solution as in Example 2containing the acetal as in Example 1 was mixed with Irgacure 2959 andcrosslinked analogously to Example 17. Water content 67±2%; transmission400-800 nm >90%.

What is claimed is:
 1. A process for the production of crosslinkedtinted mouldings, which comprises the following steps:a) preparation ofan essentially aqueous solution of a water-soluble crosslinkable tintedpolymer comprising units containing a crosslinkable group and unitscontaining a bonded reactive dye radical, b) introduction of theresultant solution into a mould, c) initiation of the crosslinking inwater or in an organic solvent in which the crosslinkable tinted polymeris dissolved, and d) opening of the mould so that the moulding can beremoved.
 2. A process according to claim 1, wherein the mouldings arecontact lenses.
 3. A process according to claim 1, wherein thewater-soluble crosslinkable tinted polymer of step a) is derived from astarting polymer containing, on or in the polymer chain, a functionalgroup which can react with a reactive dye.
 4. A process according toclaim 3, wherein the water-soluble crosslinkable tinted polymer of stepa) is derived from polyvinyl alcohol.
 5. A process according to claim 3,wherein the water-soluble crosslinkable tinted polymer of step a)comprises units in the polymer chain which are derived from thefollowing monomer units: a vinyllactam, vinyl alcohol, if desired avinyl (lower alkane)carboxylate, a vinylic crosslinking agent and, ifdesired, a vinylic photoinitiator.
 6. A process according to claim 5,wherein the polymer is a terpolymer of vinylpyrrolidone, vinyl acetateand vinyl alcohol.
 7. A process according to claim 1, wherein theessentially aqueous solution of the water-soluble crosslinkable tintedpolymer is free or essentially free from undesired constituents, suchas, in particular from monomeric, oligomeric or polymeric startingcompounds used for the preparation of this polymer, or from by-productsformed during the preparation of this polymer, or from impuritiespresent in the reactive dyes.
 8. A process according to claim 1, whereinthe essentially aqueous solution of the water-soluble crosslinkabletinted polymer is used without addition of a comonomer, in particular avinylic comonomer.
 9. A process according to claim 1, wherein aninitiator for the crosslinking is added to the solution of thewater-soluble, crosslinkable tinted polymer.
 10. A process according toclaim 1, wherein the crosslinking is not followed by extraction in orderto remove undesired constituents.
 11. A process according to claim 1,wherein the reactive dye is covalently bonded to the polymer backboneeither directly via an ether, thioether, amino or amido group or via abivalent or trivalent bridge.
 12. A process according to claim 11,wherein the bridge is a trivalent bridge derived from an ω-amino-C₁ -C₁₂alkylaldehyde acetal.
 13. A process according to claim 1, whichcomprises the following steps:a) preparation of an essentially aqueoussolution of a water-soluble crosslinkable tinted polymer comprisingunits containing a crosslinkable group and units containing a reactivedye radical covalently bonded to the polymer backbone either directly orvia a bridge, which solution is free or essentially free from undesiredconstituents, such as, in particular, from monomeric, oligomeric orpolymeric starting compounds used for the preparation of this polymer orfrom by-products formed during the preparation of this polymer, or fromimpurities present in the reactive dyes, and is used without addition ofa comonomer, b) introduction of the resultant solution into a mould, c)initiation of the crosslinking, and d) opening of the mould so that themoulding can be removed.
 14. A process according to claim 13, whereinthe mouldings are tinted contact lenses.
 15. A process according toclaim 14 for the production of a contact lens, wherein the essentiallyaqueous solution is a purely aqueous solution or a solution in anartificial, preferably buffered, tear fluid.
 16. A process according toclaim 14 for the production of a tinted contact lens, wherein acrosslinking initiator is added to the solution, and the crosslinkingtakes place by photocrosslinking.
 17. A tinted moulding, in particular atinted contact lens, obtainable by a process according to claim
 1. 18. Atinted contact lens according to claim 17, which is suitable for itsintended use without extraction.
 19. A tinted contact lens obtainableaccording to claim 14, which is suitable for its intended use withoutextraction.
 20. A crosslinkable tinted polymer comprising unitscontaining a crosslinkable group of the formula I ##STR33## in which Ris alkylene having up to 12 carbon atoms, R₁ is hydrogen or lower alkyl,and R₂ is an olefinically unsaturated, electron-withdrawing,copolymerizable radical, having up to 25 carbon atoms, and R₃ ishydrogen, a C₁ -C₆ alkyl group or a cycloalkyl group, and comprisingunits containing a covalently bonded reactive dye, where the covalentbond to the polymer backbone is, either direct via an ether, thioether,amino, imino or amido group or via a bivalent or trivalent bridge.
 21. Acrosslinkable tinted polymer according to claim 20, in which the unitscontaining a ##STR34## in which: RF' is a radical of the formula##STR35## D is a radical of an organic dye, R₁₄ is a divalentelectron-withdrawing group,U is hydrogen or halogen, R is a divalentradical of a C₁ -C₁₂ alkane, R₁ is hydrogen or C₁ -C₄ alkyl, R₃ ishydrogen, C₁ -C₆ alkyl or cycloalkyl, and Y is --O-- or -N(R₁)--.
 22. Acrosslinkable tinted polymer according to claim 21, wherein R₁ and R₃are hydrogen, R is C₁ -C₄ alkylene, and RF' and Y are as defined above.23. A crosslinkable tinted polymer according to claim 20, wherein thecovalently bonded reactive dye is derived from a reactive dye whichconforms to the general formula XVII or XIII ##STR36## in which D is aradical of an organic dye, R₁₄ is a divalent, organic,electron-withdrawing group,U is hydrogen or halogen, and V is a leavinggroup, or mixtures thereof.
 24. A crosslinkable tinted polymer accordingto claim 23, wherein D is the radical of an azo (monoazo or disazo),phthalocyanine, azomethine, nitro, metal complex or anthraquinone dye.25. A crosslinkable tinted polymer according to claim 23, wherein R₁₄ is--CO--, --SO₂ --, --SO--, --NHCO-- or --NHSO₂ --.
 26. A crosslinkabletinted polymer according to claim 21, wherein the reactive dyeradicalRF' is derived from Remazol Schwarz B (Reactive Black 5), RemazolBrillantblau R (Reactive Blue 19, Duasyn-Blau R-R), Remazol TuirkisblauG (Reactive Blue 21, Duasyn-Blau R-KG), Remazol Goldorange 3G (ReactiveOrange 78), Remazol Brillantrot F3B (Reactive Red 180, Duasyn-RotR-F3B), Remazol Gelb GR (Reactive Yellow 15), Remazol Brillantgelb GL(Reactive Yellow 37, Duasyn-Gelb R-GL), Duasyn-Gelb R-R (mixture ofReactive Yellow 17 and Reactive Yellow 15), Remazol Brillantgrun 6B(Reactive Blue 38, Duasyn-Grun R-K6B), Remazol Schwarz RL (ReactiveBlack 31, Duasyn-Schwarz R-KRL), Duasyn-Schwarz R-N (mixture of ReactiveBlack 5 and Reactive Orange 72), Remazol Brillantorange 3R (ReactiveOrange 16), Remazol Brillantblau B, Remazol Brillantblau BB, RemazolDruckschwarz G, Remazol Rot B, or Duasyn-Blau R-UG.
 27. A crosslinkabletinted polymer according to claim 20, which is a derivative of apolyvinyl alcohol having a mean molecular weight of at least about 2000which comprises from about 0.5 to about 80%, based on the number ofhydroxyl groups in the polyvinyl alcohol, of crosslinkable units of theformula I ##STR37## in which R is alkylene having up to 12 carbon atoms,R₁ is hydrogen or lower alkyl, and R₂ is an olefinically unsaturated,electron-withdrawing, copolymerizable radical, having up to 25 carbonatoms, and R₃ is hydrogen, a C₁ -C₆ alkyl group or a cycloalkyl group.28. A crosslinkable tinted polymer according to claim 27, in which R₂ isan olefinically unsaturated acyl radical of the formula R₃₀ --CO--, inwhich R₃₀ is an olefinically unsaturated, copolymerizable radical having2 to 24 carbon atoms.
 29. A crosslinkable tinted polymer according toclaim 28, in which R₃₀ is alkenyl having 2 to 8 carbon atoms.
 30. Acrosslinkable tinted polymer according to claim 27, in which the radicalR₂ is a radical of the formula II

    --CO--NH--(R.sub.4 --NH--CO--O).sub.q --R.sub.5 --O--CO--R.sub.30(II)

in which q is zero or one, and R₄ and R₅, independently of one another,are lower alkylene having 2 to 8 carbon atoms, arylene having 6 to 12carbon atoms, a saturated bivalent cycloaliphatic group having 6 to 10carbon atoms, arylenealkylene or alkylenearylene having 7 to 14 carbonatoms or arylenealkylenearylene having 13 to 16 carbon atoms, and inwhich R₃₀ is an olefinically unsaturated, copolymerizable radical having2 to 24 carbon atoms.
 31. A crosslinkable tinted polymer according toclaim 27, which is a derivative of a polyvinyl alcohol having amolecular weight of at least about 2000 which comprises from about 0.5to about 80%, based on the number of hydroxyl groups in the polyvinylalcohol, of units of the formula III ##STR38## in which R is loweralkylene, R₁ is hydrogen or lower alkyl, p has the value zero or one, qhas the value zero or one, R₃₀ is an olefinically unsaturated,copolymerizable radical having 2 to 8 carbon atoms, and R₄ and R₅,independently of one another, are lower alkylene having 2 to 8 carbonatoms, arylene having 6 to 12 carbon atoms, a saturated bivalentcycloaliphatic group having 6 to 10 carbon atoms, arylenealkylene oralkylenearylene having 7 to 14 carbon atoms or arylenealkylenearylenehaving 13 to 16 carbon atoms.
 32. A crosslinkable tinted polymeraccording to claim 31, in which R is lower alkylene having up to 6carbon atoms, p is zero and R₃₀ is alkenyl having 2 to 8 carbon atoms.33. A crosslinkable tinted polymer according to claim 31, in which R islower alkylene having up to 6 carbon atoms, p is one, q is zero, R₅ islower alkylene having 2 to 6 carbon atoms, and R₃₀ is alkenyl having 2to 8 carbon atoms.
 34. A crosslinkable tinted polymer according to claim31, in which R is lower alkylene having up to 6 carbon atoms, p is one,q is one, R₄ is lower alkylene having 2 to 6 carbon atoms, phenylene,unsubstituted or substituted by lower alkyl, cyclohexylene orcyclohexylene(lower alkylene), unsubstituted or substituted by loweralkyl, phenylene(lower alkylene), (lower alkylene)phenylene orphenylene(lower alkylene)phenylene, R₅ is lower alkylene having 2 to 6carbon atoms, and R₃₀ is alkenyl having 2 to 8 carbon atoms.
 35. Acrosslinkable tinted polymer according to claim 27, which is aderivative of a polyvinyl alcohol having a molecular weight of at leastabout 2000 which comprises from about 1 to about 15%, based on thenumber of hydroxyl groups in the polyvinyl alcohol, of units of theformula I.
 36. A compound of the formula XI ##STR39## in which thesymbols R' and R" are hydrogen or lower alkyl or lower alkanoyl, and theother symbols R₃, R, R₁ and RF' are as defined in claim
 21. 37. Acrosslinked tinted polymer obtainable by photocrosslinking acrosslinkable tinted polymer according to claim 20 in the presence orabsence of an additional vinylic comonomer.
 38. A crosslinked tintedpolymer according to claim 37, wherein said crosslinked tinted polymeris photocrosslinked in essentially pure form additional vinyliccomonomerl.
 39. A crosslinked tinted polymer according to claim 38,where the crosslinkable tinted polymer is converted into essentiallypure form by single or repeated ultrafiltration.
 40. A crosslinkedtinted polymer according to claim 37, wherein said crosslinked tintedpolymer is photocrosslinked in the absence of an additional vinyliccomonomer.
 41. A crosslinked tinted polymer according to claim 37,wherein said crosslinked tinted polymer is photocrosslinked in thepresence of from 0.5 to 80 units of an additional vinylic comonomer perunit of the formula I.
 42. A process for the preparation of acrosslinked tinted polymer according to claim 37, which comprisesphotocrosslinking said crosslinkable tinted polymer ccording to claim 20in the presence or absence of an additional vinylic comonomer.
 43. Aprocess according to claim 42, wherein the crosslinkable tinted polymeris employed in essentially pure form.
 44. A process according to claim43, wherein the crosslinkable tinted polymer is converted intoessentially pure form by single or repeated ultrafiltration.
 45. Aprocess according to claim 42, which is carried out in a solution.
 46. Atinted moulding essentially comprising a crosslinked tinted polymeraccording to claim
 37. 47. A tinted moulding according to claim 46,which is a tinted contact lens.
 48. A process for the production of atinted moulding according to claim 46, which comprises photocrosslinkingsaid crosslinkable tinted polymer in a closed mould in the presence orabsence of an additional vinylic comonomer.
 49. A process for theproduction of a tinted contact lens according to claim 47, whichcomprises photocrosslinking said crosslinkable tinted polymer in aclosed contact-lens mould by the full-mould process in the presence orabsence of an additional vinylic comonomer.